The Tammar Wallaby and Fur Seal: Models to Examine Local Control of Lactation

Mammary development and function are regulated by systemic endocrine factors and by autocrine mechanisms intrinsic to the mammary gland, both of which act concurrently. The composition of milk includes nutritional and developmental factors that are crucial to the development of the suckled young, but it is becoming increasingly apparent that milk also has a role in regulating mammary function. This review examines the option of exploiting the comparative biology of species with extreme adaptation to lactation to examine regulatory mechanisms that are present but not readily apparent in other laboratory and livestock species. The tammar wallaby has adopted a reproductive strategy that includes a short gestation (26 d), birth of an immature young, and a relatively long lactation (300 d). The composition of milk changes progressively during the lactation cycle, and this is controlled by the mother and not the sucking pattern of the young. Furthermore, the tammar can practice concurrent asynchronous lactation; the mother provides a concentrated milk high in protein and fat for an older animal that is out of the pouch and a dilute milk low in fat and protein but high in carbohydrates from an adjacent mammary gland for a newborn pouch young. This phenomenon suggests that the mammary gland is controlled locally. The second study species, the Cape fur seal, has a lactation characterized by a repeated cycle of long at-sea foraging trips (up to 28 d) alternating with short suckling periods of 2 to 3 d ashore. Lactation almost ceases while the seal is off shore, but the mammary gland does not progress to apoptosis and involution, most likely because of local control of the mammary gland. Our studies have exploited the comparative biology of these models to investigate how mammary function is regulated by endocrine factors, and particularly by milk. This review reports 3 major findings using these model animals. First, the mammary epithelial cell has an extraordinary intrinsic capacity for survival in our culture model, and the path to either function or death by apoptosis is actively driven. The second outcome is that the route to apoptosis is most likely regulated by specific milk factors. Finally, whey acidic protein, a major milk protein in some species, may play a role in normal mammary development, but that role in vivo may be limited to marsupials. Evolutionary pressure has led to changes in the structure of the protein with an accompanying change in function. Therefore, we propose that a loss of function of this protein in eutherians may relate to a reproductive strategy that is less dependent on lactation.

Characterization of two whey protein genes in the Australian dasyurid marsupial, the stripe-faced dunnart (Sminthopsis macroura)

We report the first isolation and sequencing of genomic BAC clones containing the marsupial milk protein genes Whey Acidic Protein (WAP) and Early Lactation Protein (ELP). The stripe-faced dunnart WAPgene sequence contained five exons, the middle three of which code for the WAPmotifs and four disulphide core domains which characterize WAP. The dunnart ELPgene sequence contained three exons encoding a protein with a Kunitz motif common to serine protease inhibitors. Fluorescence in situ hybridization located the WAPgene to chromosome 1p in the stripe-faced dunnart, and the ELPgene to 2q. Northern blot analysis of lactating mammary tissue of the closely related fat-tailed dunnart has shown asynchronous expression of these milk protein genes. ELPwas expressed at only the earlier phase of lactation and WAPonly at the later phase of lactation, in contrast to beta-lactoglobulin (BLG) and alpha-lactalbumin (ALA) genes, which were expressed in both phases of lactation. This asynchronous expression during the lactation cycle in the fat-tailed dunnart is similar to other marsupials and it probably represents a pattern that is ancestral to Australian marsupials.

281. The role of insulin in milk protein synthesis

The mammary explant culture model has been frequently used to mimic lactation and to examine the endocrine control of milk protein gene expression. Studies in the mouse show the expression of the milk protein genes in explants requires insulin in the presence of prolactin and cortisol. The role of insulin in milk protein synthesis in the dairy cow is not as clear. The bovine mammary explant culture model has been utilised to show that insulin is essential for alpha-s1-casein gene expression and the synthesis of the casein proteins. In addition, mouse culture experiments were undertaken to provide an insight into the underlying molecular mechanisms of insulin action in hte mammary gland. A global analysis of the genes induced in the cultured explants was done using Affymetrix microarray and showed 132 genes, including the major milk protein genes, required the complement of insulin, cortisol and prolactin for maximal expression. Twenty-seven genes showed a 3-fold change in gene expression in response to insulin. The function of these genes can be largely categorised into maintenance of cell integrity, signal transduction, transport mechanisms, cellular metabolism and a direct effect on gene transcription in the nucleus. The requirement for insulin in milk protein synthesis is highlighted by its role in inducing the STAT5 gene, known to be a key transcription factor for the milk protein genes. Interestingly, dairy cows of high genetic merit have unusually low serum concentrations of insulin. This has occured in association with a high selection pressure for milk volume that has altered the regulation of blood glucose homeostasis. Our study indicates that this intensity of selection for high milk volume could be compromising the dairy cow’s potential for milk protein production: Has selecting for milk volume in many populations of dairy cows been achieved by lowering circulating insulin levels with consequent effects on the efficiency for milk protein yield as well as compromised reproductive performance.

Sequencing and mapping hemoglobin gene clusters in the Australian model dasyurid marsupial Sminthopsis macroura

Comparing globin genes and their flanking sequences across many species has allowed globin gene evolution to be reconstructed in great detail. Marsupial globin sequences have proved to be of exceptional significance. A previous finding of a beta(beta)-like omega(omega) gene in the alpha(alpha) cluster in the tammar wallaby suggested that the alpha and beta cluster evolved via genome duplication and loss rather than tandem duplication. To confirm and extend this important finding we isolated and sequenced BACs containing the alpha and beta loci from the distantly related Australian marsupial Sminthopsis macroura. We report that the alpha gene lies in the same BAC as the beta-like omega gene, implying that the alpha-omega juxtaposition is likely to be conserved in all marsupials. The LUC7L gene was found 3' of the S. macroura alpha locus, a gene order shared with humans but not mouse, chicken or fugu. Sequencing a BAC contig that contained the S. macroura beta globin and epsilon globin loci showed that the globin cluster is flanked by olfactory genes, demonstrating a gene arrangement conserved for over 180 MY. Analysis of the region 5' to the S. macroura epsilon (epsilon) globin gene revealed a region similar to the eutherian LCR, containing sequences and potential transcription factor binding sites with homology to eutherian hypersensitive sites 1 to 5. FISH mapping of BACs containing S. macroura alpha and beta globin genes located the beta globin cluster on chromosome 3q and the alpha locus close to the centromere on 1q, resolving contradictory map locations obtained by previous radioactive in situ hybridization.

Bone morphing: 3D morphological data for total knee arthroplasty

OBJECTIVE

The clinical outcome of a total knee arthroplasty (TKA) is mainly determined by the accuracy of the surgical procedure itself. To improve the final result, one must take into account (a) the alignment of the prosthesis with respect to the mechanical axis, and (b) the balance of the soft tissues. Therefore, morphologic data (such as the shape of the epiphysis) and geometric data are essential. We present a new method for performing TKA based on morphologic and geometric data without preoperative images.

MATERIALS AND METHODS

The global method is based on the digitization of points with an optical 3D localizer. For the morphologic acquisitions, we use a method based on the registration of sparse point data with a 3D statistical deformable model. To build the mechanical axis, we use a kinematics method for the hip center and digitization of anatomical landmarks for the ankle centers. The knee center is not determined by digitization or kinematics of the knee, as this would not be accurate. The surgical planning relies totally on the soft-tissue balance, which is the key issue for a good kinematics result.

RESULTS

We have used this system for 6 months in a randomized clinical trial involving 35 patients to date. For the first 11 patients that could be measured in the navigation group, the postoperative frontal alignment was within the range of 180 +/- 3 degrees. Fluoroscopic assessment of the soft-tissue balancing will be performed at the conclusion of an extended 2-year study to evaluate the results from a functional point of view.

CONCLUSION

Bone Morphing is an accurate, fast, and user-friendly method that can provide morphologic as well as geometric data. We have introduced the important notion of soft-tissue balancing into the intraoperative planning step to optimize the kinematics as well as the anatomy. Therefore, this method should be considered as an alternative to the CT-based method.

[Long gamma nail for the treatment of subtrochanteric fracture of the femur]

PURPOSE OF THE STUDY

The standard gamma nail is commonly used for the treatment of trochanteric fractures but cannot be used if the fracture lies at the level of the distal locking. Theoretically, the long gamma nail would overcome this inconvenience and could be used for all cases of subtrochanteric and trochanteric-shaft fractures.

MATERIAL AND METHODS

Clinical and radiological charts were established in 1990 for a multicentric study. The radiology work-up included an AP view of the pelvis and an oblique lateral view of the hip. Two classifications were used: Seinsheimer and Muller as modified by Nazarian. Three stages of fracture reduction were recorded: 1=anatomic reduction, 2=acceptable reduction, 3=poor reduction. From January 1995 to December 1999, 46 patients were treated with the long gamma nail. Twenty-four cases were excluded for various reasons (from which 3 early death). 22 remaining patients were followed for more than six months. Mean age was 68 years (range 42-96); there were six women and 16 men. Ten patients were traffic or work accident victims and 12 had had a home accident.

RESULTS

Mean duration of surgery was 70 minutes. Three patients required revision surgery within a week of the initial osteosynthesis. Mean hemoglobin level before surgery was 12.9 g/dl; 8.9 g/dl during the first postoperative week. Mean hospital stay was 14 days. Weight-bearing with support was possible early after surgery in 16 patients who walked with crutches or a walker. Mean delay to weight-bearing was 11 days. At three months, all patients were using an aid for walking; at six months, four patients used a walker. Bone healing was achieved on the average at the twelfth week. Radiological reduction was anatomic in four, acceptable in three and poor in 15.

DISCUSSION

We advocate the AO classification as it allows a structured analysis of all fractures within a unique system. We compared our results with nine series reported in the literature using other therapeutic methods (screw-plate, nail-plate, Ender nail). The operative time for the long gamma nail (70 min) was comparable with that for other surgical techniques. Treatment with the long gamma nail favors bone healing and limits the risk of infection. Radiological results in our series were poor, but there were no cases with nonunion and the morbidity was low.

Pedicle island flaps of latissimus dorsi. Applications in surgical repair of ruptures of the rotator cuff

There are considerable problems in repair of major ruptures of the rotator cuff tendons particularly those of the supra and infraspinatus mm. The Gerber technique only transfers the tendinous insertion of the latissimus dorsi onto the greater tuberosity in massive cuff ruptures. We have extended this approach. In 12 shoulders, we studied the feasibility of a latissimus dorsi transfer harvested to fit and bearing muscle and tendon detached at its two extremities and transposed as a neurovascular island. The muscular part is transferred to the infra or supraspinous fossae and the tendon to the greater tuberosity with the aim of reactivating the infra and supraspinatus muscles. The lateral bundle of the latissimus dorsi is always transferable on its neurovascular pedicle into the infraspinous fossa, even into the supraspinous fossa, or into both if transfer is used as a bilobed flap. This anatomical work allowed a parallel study of the different possibilities of transposing the neurovascular pedicle, which might limit the technique, and also to determine the most appropriate surgical approach.

The use of MR images to evaluate the risks associated with proximal locking of intramedullary tibial nails

Vascular complications associated with locked intramedullary tibial nailing are infrequent but always serious, with a secondary amputation rate of 30%. These complications, based on an MR study of the anatomic relationships between the interlocking screws and the neurovascular or articular structures at the proximal end of the tibia, have been analysed. Two types of nails were used: one with anterior-posterior locking and a specially designed prototype with oblique locking. In particular this study emphasised the anatomic risk of injury to the popliteal structures when using anterior-posterior locking, as well as to the anterior tibial vessels and proximal tibiofibular joint when using oblique locking. As no locking method appears to be better than any other, the best is that associated with the lowest morbidity. Consequently, the use of frontal instead of anterior-posterior locking is recommended; the use of oblique locking, which this study has shown carries a much higher risk of complications, is strongly advised against.

[Bilateral bipartite carpal scaphoid bone: a congenital disease or unrecognized pseudarthrosis? Discussion a propos of a clinical case]

PURPOSE OF THE STUDY

Bipartite scaphoid has long been debated, and is of traumatic origin for some authors or congenital for others. The aim of the study is to distinguish clinical and radiographic criteria for the diagnosis of congenital bipartite scaphoid.

MATERIAL AND METHOD

A case of bilateral bipartite scaphoid is presented. To distinguish pseudarthrosis from congenital bipartite scaphoid we used, the revised carpal height ratio of Nattrass, the CT, and magnetic resonance imaging.

RESULTS

These examinations showed no collapse and they revealed evidence of articular cartilage around the fragments with the same thickness in all the carpus.

CONCLUSION

We believe that congenital origin is more probable but we recommend to follow the patient, with yearly standard wrist radiograph and use, the revised carpal height ratio of Nattrass to research a carpal shift or collapse.

New susceptibility locus for rheumatoid arthritis suggested by a genome-wide linkage study

Rheumatoid arthritis (RA), the most common autoimmune disease, is associated in families with other autoimmune diseases, including insulin-dependent diabetes mellitus (IDDM). Its genetic component has been suggested by familial aggregation (lambdas = 5), twin studies, and segregation analysis. HLA, which is the only susceptibility locus known, has been estimated to account for one-third of this component. The aim of this paper was to identify new RA loci. A genome scan was performed with 114 European Caucasian RA sib pairs from 97 nuclear families. Linkage was significant only for HLA (P < 2.5.10(-5)) and nominal for 19 markers in 14 other regions (P < 0.05). Four of the loci implicated in IDDM potentially overlap with these regions: the putative IDDM6, IDDM9, IDDM13, and DXS998 loci. The first two of these candidate regions, defined in the RA genome scan by the markers D18S68-D18S61-D18S469 (18q22-23) and D3S1267 (3q13), respectively, were studied in 194 additional RA sib pairs from 164 nuclear families. Support for linkage to chromosome 3 only was extended significantly (P = 0.002). The analysis of all 261 families provided a linkage evidence of P = 0. 001 and suggested an interaction between this putative RA locus and HLA. This locus could account for 16% of the genetic component of RA. Candidate genes include those coding for CD80 and CD86, molecules involved in antigen-specific T cell recognition. In conclusion, this first genome scan in RA Caucasian families revealed 14 candidate regions, one of which was supported further by the study of a second set of families.

[Surgical treatment of freshly closed articular fractures of proximal interphalangeal joints]

Eleven fractures of the base of P2 and 8 fractures of the head of P1 were treated surgically. We review the results after a mean follow-up of 4 years 5 months. Due to their complexity is no real consensus on the treatment of P2 and various treatments were used. This series demonstrated two points: first the was no correlation between the degree of patient satisfaction and the section of digital immobilization; second, residual subluxation and/or arthrosic remodeling was frequent but was not incompatible with a good objective and subjective outcome.

[Use of muscular flaps for the treatment of open fractures of limbs. Apropos of 42 cases]

PURPOSE OF THE STUDY

Since 1988, skin defect associated with upper (6 cases) or lower (34 cases) limb fractures were treated in our Orthopaedic Department with regional or free muscular flaps. The aim of this study was to demonstrate that muscular flaps represent a treatment of choice for infection prevention and consolidation.

MATERIAL AND METHODS

42 patients have been treated: 29 Cauchoix III or IV, 12 secondary exposed fractures, 1 amputation. A total of 42 flaps, including 28 regional flaps and 14 microvascular free-tissue transfers were performed. A first stage included thorough debridement, fixation with external fixator in 85 per cent, and revascularization (4 cases). A second look was necessary in all but 3 cases: flap coverage was performed at this stage. A bone graft was proposed in 17 cases after a mean time of 3 months and 20 days.

RESULTS

Bony healing was found in 37 cases (86.5 per cent) with a mean delay of 7 months 20 days. 5 patients required another method of treatment because of flap necrosis or non-union, with an average time to bony healing of 13 months. 42 tissue transfers were performed with an overall success rate of 95.3 per cent (2 necrosis of latissimus dorsi flaps). 3 partial necrosis involved 2 regional and 1 free flap. One of them needed another treatment. No infection was encountered in 40 cases (95 per cent) even if most of the patients were treated after initial treatment elsewhere.

DISCUSSION

Experience with regional muscle transfer has advocated the gastrocnemius and proximal pedicle medial soleus as reliable and excellent choice for reconstruction of the proximal and middle third of the leg. Latissimus dorsi transfer, which can be used totally, partially, or as a "vascular graft flap" represent the treatment choice for extensive upper or lower limb exposed fracture especially for distal lower limb fracture (exposure of the tibia). Muscle flap coverage in the acute period (within 48 or 72 hours) remains for us the best treatment.

Osteoarthritis of the pisiform-triquetral compartment. A review of eight cases of an underrecognized entity

Seven patients (eight hands) with pain suggestive of the pisiform-triquetral compartment were studied to compare outcomes after surgical excision of the pisiform (four hands) and after conservative therapy (four hands). All patients were reevaluated by a rheumatologist who was not involved in their treatment. The efficacy of conservative therapy was mediocre in every case. Although it is reasonable to assume that the surgically-treated patients had more severe manifestations at baseline, all were free of symptoms at reevaluation, versus none of the conservatively-treated patients. After two years, excision of the pisiform yielded excellent results with no adverse effects on range of motion or grip strength. Despite the small size of our sample and the relatively low incidence of pisitriquetral osteoarthritis, our data suggest that surgery is preferable over conservative therapy in this condition.

A novel tandem repeat sequence located on human chromosome 4p: isolation and characterization

In an effort to analyze the genomic region of the distal half of human chromosome 4p, to where Huntington disease and other diseases have been mapped, we have isolated the cosmid clone (CRS447) that was likely to contain a region with specific repeat sequences. Clone CRS447 was subjected to detailed analysis, including chromosome mapping, restriction mapping, and DNA sequencing. Chromosome mapping by both a human-CHO hybrid cell panel and FISH revealed that CRS447 was predominantly located in the 4p15.1-15.3 region. CRS447 was shown to consist of tandem repeats of 4.7-kb units present on chromosome 4p. A single EcoRI unit was subcloned (pRS447), and the complete sequence was determined as 4752 nucleotides. When pRS447 was used as a probe, the number of copies of this repeat per haploid genome was estimated to be 50-70. Sequence analysis revealed that it contained two internal CA repeats and one putative ORF. Database search established that this sequence was unreported. However, two homologous STS markers were found in the database. We concluded that CRS447/pRS447 is a novel tandem repeat sequence that is mainly specific to human chromosome 4p.

Texas Res-X and rhodamine Red-X, new derivatives of sulforhodamine 101 and lissamine rhodamine B with improved labeling and fluorescence properties

Texas Red sulfonyl chloride (TR-SC) and Lissamine rhodamine B sulfonyl chloride (LRB-SC) are popular dyes often used to prepare red fluorescent conjugates that are useful second labels in combination with fluorescein. Unfortunately, being sulfonyl chloride derivatives, both are unstable to moisture during storage and prone to hydrolysis in the conjugation reaction. Their instability causes the percentage of reactive dye to vary from lot to lot and requires use of low temperatures and a relatively high pH to optimize conjugation efficiency. Succinimidyl esters of the aminohexanoic acid sulfonamides of both dyes have been prepared, which are designated Texas Red-X succinimidyl ester (TR-X-SE) and Rhodamine Red-X succinimidyl ester, respectively. Their spectral properties are similar to those of their sulfonyl chloride analogs; moreover, incorporation of the succinimidyl ester at the end of the aliphatic chain spacer facilitates conjugation, decreases precipitation of proteins during conjugation and storage, and usually increases the fluorescence yield of the conjugate. Comparison of the rate of hydrolysis of TR-SC with that of TR-X-SE shows that, while the former was completely hydrolyzed within 5 min by exposure to water, TR-X-SE retains most of its reactivity for more than an hour. The reactivity of both new derivatives is high between pH 7.5 and 8.5, allowing conjugation of proteins that do not tolerate the high pH required for reaction with sulfonyl chlorides. In addition, Texas Red maleimides and haloacetamides containing spacer groups were prepared for labeling sulfhydryl groups. A Texas Red-X derivative of phalloidin has also been prepared, and its use for labeling F-actin has been characterized.

Modeling and analysis of 3-D elongated shapes with applications to long bone morphometry

Presents a geometric model to be used as a framework for the description and analysis of three-dimensional (3-D) elongated shapes. Elongated shapes can be decomposed into two different parts: a 3-D curve (the central axis) and a 3-D surface (the straight surface). The central axis is described in terms of curvature and torsion. A novel concept of torsion image is introduced which allows the user to study the torsion of some relevant 3-D structures such as the medulla of long bones, without computing the third derivative. The description of the straight surface is based on an ordered set of Fourier Descriptors (FDs), each set representing a 2-D slice of the structure. These descriptors possess completeness, continuity, and stability properties, and some geometrical invariancies. A polar diagram is built which contains the anatomical information of the straight surface and can be used as a tool for the analysis and discrimination of 3-D structures. A technique for the reconstruction of the 3-D surface from the model's two components is presented. Various applications to the analysis of long bone structures, such as the ulna and radius, are derived from the model, namely, data compression, comparison of 3-D shapes, segmentation into 3-D primitives, and torsion and curvature analysis. The relevance of the method to morphometry and to clinical applications is discussed.