Sex chromosomes in lizards.

Karyotypes of many species of the genus Sceloporus support the generalization that there are no morphologically recognizable sex chromosomes in lizards; however, there is a marked sexual dimorphism in the karyotypes of Sceloporus jarrovi and Sceloporus poinsetti. During meiosis in males, whose diploid number of chromosomes is 31, preferential segregation of chromosomes from a trivalent results in heterogamety.

Local control of muscle-invasive bladder cancer: preoperative radiotherapy and cystectomy versus cystectomy alone.

PURPOSE: The role of preoperative radiotherapy for patients with muscle-invasive bladder cancer remains controversial. Since 1985, the primary modality for treatment of these patients at our institution has been radical cystectomy alone. Prior to that time, the use of preoperative and cystectomy had been the mainstay of treatment. In this retrospective review we compare the results of these treatments, focusing on local control. METHODS AND MATERIALS: The preoperative radiotherapy and radical cystectomy (PREOP) group was comprised of 338 patients with muscle-invasive (Stages T2-T4) transitional cell carcinoma of the bladder treated between 1960 and 1983. A mean total dose of 49.3 +/- 0.2 Gy (+/- SE) was administered at 2 Gy per fraction 4-6 weeks prior to cystectomy. The radical cystectomy alone (CYST) group was comprised of 232 patients treated between 1985 and 1990. The median follow-up for the PREOP group was 91 months and for the CYST group was 54 months. Only those patients who completed planned PREOP (n = 301) and CYST (n = 220) treatments were included in the analyses described below. RESULTS: The treatment groups were stratified by clinical stage and compared in terms of actuarial local control. There were no differences between the groups for Stage T2 or T3a patients, and there were not enough Stage T4 patients in the PREOP group with which to make a meaningful comparison. However, for those with T3b disease, actuarial 5 year local control for the PREOP group (n = 92) was 91%, compared to 72% for the CYST group (n = 43). This difference was significant at p = 0.003 (log rank). Patients with T3b disease who received PREOP also fared slightly better at 5 years in terms of freedom from distant metastasis (67% vs. 54%), disease freedom (59% vs. 47%), and overall survival (52% vs. 40%); although, these differences did not reach statistical significance. The distribution of prognostic factors in the groups was analyzed to determine if this could account for the differences in local control in Stage T3b patients. For patients with Stage T3b disease, the only significant difference was by grouped age (p < 0.05, chi-square), which was not a significant factor in the univariate analyses of local control. A multivariate analysis using Cox proportional hazards models revealed pretreatment hemoglobin, blood urea nitrogen (BUN) concentration, and treatment type (PREOP vs. CYST) to be independently predictive of local control. CONCLUSION: We document here in a large number of patients treated at a single institution that preoperative radiotherapy had a significant impact on local control for patients with clinical Stage T3b disease. Because the CYST patients were treated using modern-day surgical techniques and 80% of those with Stage T3b disease received multiagent chemotherapy, it is probable that any biases, if present, would favor the CYST group. Thus, the differences between PREOP and CYST described may be underestimated. Preoperative radiotherapy should be considered as an adjunct to chemotherapy and surgery for clinical Stage T3b patients.

Significance of downstaging in muscle-invasive bladder cancer treated with preoperative radiotherapy.

PURPOSE: The relationship between clinical-to-pathologic downstaging and patient outcome following preoperative radiotherapy was examined, focusing on the mechanism (selection vs. treatment effect) responsible for the benefit seen from such downstaging. METHODS AND MATERIALS: Three hundred and one patients were treated with preoperative radiotherapy plus cystectomy (PREOP) to a median dose of 50 Gy in 25 fractions between 1960-1983. These patients were compared to 225 patients treated with radical cystectomy, with or without chemotherapy (CYST), between 1984-1990. Multiagent chemotherapy was given to 68% of those in the CYST group and was not given to any in the PREOP group. Lymph node involvement was not formally evaluated in the PREOP group, while 20% had pathologic involvement in the CYST group. RESULTS: Clinical-to-pathologic downstaging (P < T stage) was found in 73% treated with PREOP and 29% treated with CYST (p < 0.0001, chi-square). The only factors that correlated with P < T staging for the PREOP and CYST groups when each was considered separately were clinical stage, blood urea nitrogen level, and creatinine level (p < 0.05, chi-square). Multivariate logistic regression revealed that treatment (PREOP vs. CYST) correlated independently with P < T staging (p < 0.0001). The relationship of actuarial local control to distant metastasis at 5 years in patients that were downstaged, as stratified by clinical stage and treatment, was then examined. Local control rates for P < T staged T2/T3a patients were independent of treatment (PREOP vs. CYST), while distant metastasis rates were significantly greater for those in the PREOP group. In contrast, P < T staged T3b patients in the PREOP group had significantly better local control and distant metastasis rates. CONCLUSIONS: Significantly higher P < T staging rates were observed with PREOP as compared to CYST, and this was a consequence of the radiotherapy given. The relationship of downstaging from radiotherapy to local control and distant metastasis was contingent on clinical stage. The results of Stage T2/T3a and T3b patients were divergent and supported treatment effect, rather than selection, as the mechanism consistent with the patient outcomes observed.

Intercellular adhesion molecule-1 in proliferative vitreoretinopathy.

PURPOSE: To measure vitreous levels of the soluble intercellular adhesion molecule (sICAM-1) in eyes with rhegmatogenous retinal detachment (RRD) complicated or uncomplicated by proliferative vitreoretinopathy (PVR) to investigate whether levels of this molecule related to history of previous retinal surgery or to the duration and severity of PVR. METHODS: The authors measured vitreous sICAM-1 by enzyme-linked immunosorbent assay in 28 eyes with PVR and 35 eyes with uncomplicated RRD. Vitreous from 10 eyes with macular holes and from 12 cadaveric eye donors were used as control specimens. RESULTS: Vitreous sICAM-1 levels were higher in the group with RRD complicated by PVR as a whole than in the group with RRD alone or in the control groups. In patients with no previous retinal surgery, there was no difference in vitreous sICAM-1 levels between the groups with RRD alone and RRD complicated by PVR. However, in patients who had undergone previous external surgery, those with PVR showed higher levels of vitreous sICAM-1 than those with RRD alone. In PVR, raised levels of sICAM-1 were associated preferentially with a history of previous vitrectomy as well as with a longer duration of the condition, although these levels were not related to the grade of PVR. In eyes with RRD alone, the levels of sICAM-1 were not enhanced with the duration of the detachment. Despite showing high vitreous levels of sICAM-1, patients with PVR did not exhibit increased serum levels of this adhesion molecule. CONCLUSIONS: The current observations suggest that those persons in whom PVR develops may have an impairment of the mechanisms that control the inflammatory response to retinal trauma. Persistently raised vitreous levels of sICAM-1 point to the continued operation of cytokine-mediated vascular reactions at the blood-retinal barrier.

Cardiac function during laparoscopic vs open gastric bypass.

BACKGROUND: Hypercarbia and increased intraabdominal pressure during prolonged pneumoperitoneum can adversely affect cardiac function. This study compared the intraoperative hemodynamics of morbidly obese patients during laparoscopic and open gastric bypass (GBP). METHODS: Fifty-one patients with a body mass index (BMI) of 40-60 kg/m2 were randomly allocated to undergo laparoscopic (n = 25) or open (n = 26) GBP. Cardiac output (CO), mean pulmonary artery pressure (MPAP), pulmonary artery wedge pressure (PAWP), central venous pressure (CVP), heart rate (HR), and mean arterial pressure (MAP) were recorded at baseline, intraoperatively at 30-min intervals, and in the recovery room. Systemic vascular resistance (SVR) and stroke volume (SV) were also calculated. RESULTS: The two groups were similar in terms of age, weight, and BMI. Operative time was longer in the laparoscopic than in the open group (p < 0.05). The HR and MAP increased significantly from baseline intraoperatively, but there was no significant difference between the two groups. In the laparoscopic group, CO was unchanged after insufflation, but it increased by 5.3% at 2.5 h compared to baseline and by 43% compared to baseline in the recovery room. In contrast, during open GBP, CO increased significantly by 25% after surgical incision and remained elevated throughout the operation. CO was higher during open GBP than during laparoscopic GBP at 0.5 h and at 1 h after surgical incision (p < 0.05). During laparoscopic GBP, CVP, MPAP, and SVR increased transiently and PAWP remained unchanged. During open GBP, CVP, MPAP, and PAWP decreased transiently and SVR remained unchanged. There was no significant difference in the amount of intraoperative fluid administered during laparoscopic (5.5 +/- 1.6 L) and open (5.6 +/- 1.7 L) GBP. CONCLUSION: Prolonged pneumoperitoneum during laparoscopic gastric bypass does not impair cardiac function and is well tolerated by morbidly obese patients.

Expression of hematopoietic cell markers by retinal pigment epithelial cells.

PURPOSE: We investigated the expression of various isoforms of the hematopoietic cell marker CD45 on retinal pigment epithelial cells in relation to their expression of CD68 and the cytokine-reactive intercellular adhesion molecule-1 (ICAM-1). We also determined the effect of the pro-inflammatory cytokines IL-1 beta, TNF alpha and IFN gamma on the expression of these molecules by RPE cells in culture. METHODS: Monolayers of RPE cells between 3rd and 7th passages were cultured in the presence or absence of cytokines, followed by immunohistochemical staining for CD45 (170-220 kD), CD45RA (205 and 220 kD), CD45RO (180 kD), CD68 and ICAM-1, using the alkaline phosphatase-anti-alkaline phosphatase (APAAP) technique. Total (membrane and cytoplasmic) expression of each of the three CD45 isoforms was determined by enzyme-linked immunoassays (ELISA). RESULTS: The majority of RPE cells expressed all isoforms of CD45 on their membranes and the pattern of expression of these molecules was not modified by culture. The greatest intensity of membrane staining was consistently observed with antibodies to CD45RA (205 + 220 kD), while CD45 (170-220 kD) showed to be the predominant isoform within the whole cell, as judged by ELISA assays. Unlike the membrane expression of CD45, only 20% of RPE cells stained for the macrophage surface molecule CD68 following 4 h of culture, but progressive increase in the proportion of CD68 positive cells was observed by extending the culture to 24 and 48 h. Neither the expression of CD68 nor the various isoforms of CD45 were modified by incubation with pro-inflammatory cytokines. Staining for ICAM-1 was observed in 21-25% of RPE cells throughout the 48 h culture. However, incubation with 50 pg/ml of IL-1 beta, TNF alpha and IFN gamma caused a marked increase in the RPE cell expression of ICAM-1 following 4, 24 and 48 h culture. CONCLUSIONS: The observations suggest that hematopoietic cell markers are constitutively expressed on RPE cells and that functions governed by these molecules are not influenced by pro-inflammatory signals. Expression of hematopoietic molecules by RPE cells may influence the macrophage-like properties of these cells and may also aid in the identification of RPE cells during pathological processes, particularly in the proliferative retinopathies, where these cells undergo phenotypic and functional changes.

Emerging roles for MEF2 transcription factors in memory.

In the brain, transcription factors are critical for linking external stimuli to protein production, enabling neurons and neuronal networks to adapt to the ever-changing landscape. Gene transcription and protein synthesis are also vital for the formation of long-term memory. Members of the myocyte enhancer factor-2 (MEF2) family of transcription factors have a well-characterized role in the development of a variety of tissues, but their role in the adult brain is only beginning to be understood. Recent evidence indicates that MEF2 regulates the structural and synaptic plasticity underlying memory formation. However, in stark contrast to most other transcription factors implicated in memory, MEF2-mediated transcription constrains (rather than promotes) memory formation. Here, we review recent data examining the role of MEF2 in adult memory formation in rodents.

The lateral tarsal strip in ectropion surgery: is it effective when performed in isolation?

PURPOSE: The lateral tarsal strip (LTS) for involutional ectropion is often performed with a medial spindle (tarsoconjunctival diamond excision). We aimed to evaluate how well the LTS alone can achieve symptomatic relief. METHODS: A retrospective, comparative case series was performed on consecutive patients undergoing LTS alone or with medial spindle for involutional ectropion. Outcomes for LTS alone were clinically derived functional success (improvement in symptoms and aesthetic appearance) and anatomical success (judged by punctal position in the tear lake, punctal movement during blinking and absence of ectropion). We verified if these outcomes compared favourably with those of the patients who had undergone an LTS with medial spindle. Procedure selection was based on pre-operative clinical examination, especially the lateral pinch and twist test (this is described). Complications were also recorded. RESULTS: Of 67 eyes, 23 had LTS alone and 44 had LTS with a medial spindle. Of those having LTS alone the functional success rate was 87% (95% CI (66.4, 97.2%)). This did not differ significantly from a success rate of 89% (75.4, 96.2%) in LTS with a medial spindle (P=0.99). A total of 78% (56.9, 92.5%) of patients undergoing LTS had a good anatomical result compared with 82% (67.3, 91.8%) of those who had an additional medial spindle (P=0.75). Complication rates were similar between the groups. CONCLUSION: Where the lateral pinch and twist test returns the eyelid to a good position, the LTS alone can suffice for the management of involutional ectropion.

Cataract extraction after retinal detachment repair by vitrectomy: visual outcome and complications.

AIMS: To determine the intraoperative and postoperative complications and visual outcome of eyes undergoing cataract extraction after previous retinal detachment repair by pars plana vitrectomy (PPV). METHODS: Retrospective analysis of 72 patients who had cataract extraction by phacoemulsification having had retinal detachment repair by vitrectomy and internal tamponade. RESULTS: Best-corrected visual acuity (BCVA) had improved in 53 (74%) of eyes at 3 weeks after cataract surgery and 65 (90%) at final follow-up. Fifty-three eyes (74%) attained 6/12 visual acuity at final follow-up compared with 19 (26%) eyes with a preoperative vision better than 6/12. There was a significant improvement in BCVA after cataract extraction (P<0.001). Poor vision was usually related to retinal comorbidity.Intraoperative events occurred in nine eyes (12.5%) including capsulorrhexis tears, zonular dehiscence and vitreous loss. Postoperative events occurred in 15 eyes (20.8%). Retinal re-detachment occurred in four eyes (5.6%). CONCLUSIONS: Cataract extraction after retinal detachment surgery by vitrectomy generally results in a significant visual improvement, however, there is an increased intraoperative and postoperative complication rate. The risk of retinal re-detachment may previously have been underestimated.

A new technique of combined retinal and choroidal biopsy.

AIMS: To evaluate a new technique in large retinal and choroidal biopsies in patients with uveitis of unknown aetiology and chorioretinal lesions or infiltrate. METHODS: Retrospective, non-comparative, consecutive interventional case series. Patients were identified from the computerised patient database and from histopathology records. RESULTS: A total of nine patients were included in the study. The commonest indication of biopsy was panuveitis of unknown aetiology. Positive histological diagnoses from the chorioretinal biopsies were made in five cases (55.6%). Complications included vitreous haemorrhages and one case of retinal detachment. CONCLUSION: The technique of large chorioretinal biopsy described appears to be safe. It produced good amounts of chorioretinal tissue for histopathological analysis. Positive histology results were seen in the majority of the sample and especially in those where vitreous biopsy alone proved to be inadequate.

Medical uses of cosmetic colored contact lenses.

PURPOSE: To explore the clinical issues surrounding the use of hand-painted contact lenses for medical indications and to assess patient satisfaction with the use of these lenses for an unsightly eye. METHODS: A questionnaire was sent to all patients visiting the contact lens department of Western Eye Hospital for a colored contact lens fitting during a 1-year period. The questionnaire related to patient satisfaction with the lenses and aspects of wear. RESULTS: Replies were received from 25 of a total of 33 patients. The average wearing time was 11.3 hours per day. Most (88%) patients wore lenses for cosmetic reasons, and 12% wore lenses for cosmetic and refractive purposes. Satisfaction was 76% regarding lens comfort and 88% regarding lens color. CONCLUSIONS: Provided lens care is satisfactory and the patient does not have unreasonable expectations, a tinted contact lens can be a useful device. In view of the cost implication, this is a valuable service provided by the hospital.

Origin of the unisexual lizard Gymnophthalmus underwoodi (Gymnophthalmidae) inferred from mitochondrial DNA nucleotide sequences.

Analysis of variation in nucleotide sequences in mitochondrial DNA genes among species of Gymnophthalmus supports three major conclusions. First, samples of G. underwoodi, a unisexual species of hybrid origin, have identical nucleotide sequences, supporting the hypothesis that all individuals from localities in the Guianan Region of South America and the Lesser Antilles descended from a single hybridization event. Second, G. underwoodi and G. cryptus share derived similarities in nucleotide sequences of the maternally inherited mitochondrial DNA, suggesting that the female participant in the hybridization event that produced the hybrid species was either G. cryptus or most closely related to it. Last, phylogenetic analyses recovered historical structure among population samples of G. speciosus supporting previous claims that there is unrecognized diversity under that binomial, and some analyses suggest that G. speciosus does not comprise a natural group.

Parthenogenetic reptiles: new subjects for laboratory research.

Problems preventing establishment of laboratory colonies of parthenogenetic lizards have been solved. Now, productive colonies of these lizards, which have remarkably little genetic variation, can be readily established and used not only for research on parthenogenesis but also for many kinds of experiments for which reptile systems are desirable. Research colonies can provide valuable specimens while reducing the exploitation of natural populations.

Parthenogenetic lizards as vertebrate systems.

Unisexual (all-female) lizards of the genus Cnemidophorus are well suited for research in oogenesis, embryogenesis, nutrition, immunology, sex determination, genetics and the effects of aging and exposure to pathogens and chemicals, in addition to evolutionary biology. Individuals produce clones by means of parthenogenesis, and both diploid and triploid parthenogens exist. In addition, there are closely related bisexual (gonochoristic) species of Cnemidophorus. Advantages and disadvantages of maintaining laboratory colonies of Cnemidophorus are discussed.

Rapid screening of DNA diversity using dot-blot technology and allele-specific oligonucleotides: maternity of hybrids and unisexual clones of hybrid origin (lizards, Cnemidophorus).

Allele-specific oligonucleotide probes, together with dot-blot methods, can provide rapid and inexpensive screening of DNA types in large samples of organisms. Here we demonstrate their use in: (1) determining types of mitochondrial DNA in hundreds of lizards from a dynamic hybrid zone; (2) discovering intraspecific geographic variation in genes; and (3) determining and verifying the maternal ancestry of unisexual, parthenogenetic lizards in clones of hybrid origin. These methods are broadly applicable in research involving rapid screening of DNAtypes in large samples of specimens for any gene with sequence data from which to design specific probes.

The relationship of local control to distant metastasis in muscle invasive bladder cancer.

PURPOSE: We examined the relationship of local failure to distant metastasis in patients with muscle invasive bladder cancer. MATERIALS AND METHODS: This retrospective review included 240 patients treated with radical cystectomy with or without multiagent chemotherapy at our institution between 1984 and 1990 for clinical stage T2 to T4 transitional cell carcinoma of the bladder. The distribution of patients by clinical stage was 89 T2, 77 T3a, 51 T3b and 23 T4. Median followup was 55 months. RESULTS: The actuarial 5-year local control, freedom from distant metastasis and overall survival rates were 80%, 68% and 52%, respectively. There was a profoundly significant relationship between local failure and distant metastasis with distant metastasis in 56% of those with local failure. The actuarial 5-year freedom from distant metastasis rate for those with local control was 77% compared to 29% for those with local failure (p < 0.0001, log rank test). This relationship held when the group was subdivided by stage and when only cases of complete cystectomy were analyzed. The significance of this finding in light of the possible contribution of potential prognostic factors was examined. Univariate analyses revealed late clinical stage, abnormal pretreatment serum creatinine levels, the administration of chemotherapy, late pathological stage and lymph node involvement to correlate significantly with distant metastasis rates. Multivariate analyses using Cox proportional hazards models with freedom from distant metastasis as the end point revealed pathological stage, local failure and lymph node involvement to be the only significant covariates. CONCLUSIONS: Since local failure highly correlated with distant failure, treatment planning to optimize local control should be of foremost concern for those at high risk of failure by this mode (for example patients with T3b/4 disease). New treatment strategies, such as the use of preoperative radiotherapy as an adjunct to chemotherapy and radical surgery, should be considered in this high risk population.

Evidence of chronic inflammation in retina excised after relaxing retinotomy for anterior proliferative vitreoretinopathy.

BACKGROUND: Epiretinal membranes from eyes with proliferative vitreoretinopathy (PVR) frequently express molecules associated with chronic inflammation. To investigate the extent to which inflammation may compromise the detached retina, we determined the expression of inflammatory molecules in anterior retina removed after relaxing retinotomy for retinal detachment complicated by anterior PVR. METHODS: Surgical retinal specimens were studied immunohistochemically for the distribution of the vascular cell adhesion molecules VCAM, E-selectin, P-selectin, ICAM and PECAM and for the presence of the cytokine TNF alpha and of T lymphocytes (CD3-positive cells), macrophages (CD68-positive cells) and HLA-DR molecules. The findings were compared with those in control cadaveric retina. RESULTS: Aberrant expression of ICAM-1 was observed in four of nine retinal specimens from eyes with PVR, whereas its expression in control retinas was confined to the external limiting membrane and ganglion cell layers. PECAM was observed in seven of nine surgical retinal specimens and in four of five controls. E-selectin and P-selectin were expressed within the luminal aspects of four of nine retinal specimens from eyes with PVR, and VCAM was present in three of nine surgical specimens investigated. All cadaveric control retinas were negative for E-selectin and VCAM, whilst one was positive for P-selectin. Staining for TNF alpha was observed within luminal aspects and walls of retinal vessels from eight of nine surgical specimens, but was not seen in any of the cadaveric controls. T lymphocytes and cells expressing the macrophage marker CD68 were identified in two and seven of nine diseased retinas respectively, but not in any of the controls. Cells staining for HLA-DR were observed in eight of nine surgical retinal specimens and in three of five controls. CONCLUSION: The present findings indicate that retina from eyes with advanced PVR may itself be subject to inflammatory changes, and indicate that the PVR process is not limited to retinal membranes, but involves a more widespread distribution of inflammation than is generally appreciated.

Postoperative radiation of free jejunal autografts in patients with advanced cancer of the head and neck.

BACKGROUND: Free jejunal autografts increasingly are being used to repair the pharynx after resections of head and neck carcinomas. Doses of greater than 45 Gy are generally considered to be above the tolerance of the small bowel, whereas the dose range for effective postoperative radiotherapy of advanced head and neck cancers is between 57.6 Gy and 63 Gy. Between July 1988, and December, 1992, 29 patients at the M. D. Anderson Cancer Center were treated with a combination of resection of the advanced head and neck cancer, reconstruction with free jejunal autograft, and postoperative radiation. Planned reductions in postoperative doses due to the presence of the jejunum within the field were not made. This retrospective study analyzes the outcome of these patients with attention to survival, local-regional control, and complications. METHODS: Twenty-seven of the 29 study patients had squamous cell carcinoma of the larynx or pharynx; 24 of these patients had Stage III or Stage IV disease. Two patients had recurrent papillary thyroid carcinoma. The median number of days from surgery to the start of radiation was 34. Radiation doses to the tumor bed ranged from 50 Gy to 72 Gy. The median doses to the tumor bed and the jejunal autograft were both 63 Gy. Surviving patients were followed from 12 to 68 months (median, 20 months) from the time of their surgery. RESULTS: The actuarial 2-year survival rate was 51%. Nine patients had local or regional recurrences above the clavicles. The 2-year local-regional control and freedom from relapse rates were 71 and 50%, respectively. The most severe complication during radiation was confluent mucositis in greater than 50% of the treated area, which developed in two patients. No patient developed a late complication related to the jejunal autograft. CONCLUSIONS: Postoperative radiation to free jejunal autografts used for pharyngeal reconstruction can be delivered safely. Doses in this setting of 57.6 Gy to 63 Gy depending on the anticipated risk of recurrence based on clinical, surgical, and pathologic findings are recommended. The presence of a free jejunal autograft did not require a reduction of the desired doses used for patients with postoperatively irradiated head and neck cancer.