Update of the Swedish Two-County Trial of breast cancer screening: histologic grade-specific and age-specific results

The benefit of mammographic screening in reducing mortality from breast cancer is well established. Questions remain with respect to the magnitude of the long-term benefit of modern mammography screening, age specific benefits and the timing of these, and histology specific effects.

METHODS

The Swedish Two-County Trial was set up in 1977, with 77,080 women aged 40-74 randomised to invitation to mammographic screening for breast cancer (active study population, ASP) and 55,985 women randomised to no invitation (passive study population, PSP). There is now follow-up for mortality to 31 December 1996, approximately 18 years average follow-up. We investigated the effect of invitation of screening on breast cancer mortality and incidence of advanced tumours by age group (40-49 and 50-74) and histologic type. In addition we estimated progression rates by histologic grade using markov chain models.

RESULTS

A significant 29% reduction in breast cancer mortality was observed in association with invitation to screening (relative risk = 0.71, 95% confidence interval 0.60-0.83), maintaining the effect observed at previous stages of follow-up. Age-specific analyses show a smaller and later mortality benefit in women aged 40-49. This is related to the fact that there is a considerable benefit from early detection in terms of mortality from aggressive, poorly differentiated cancers in women aged 50-74, whereas the major effect in women aged 40-49 is on the less aggressive tumours of good or intermediate differentiation. Among women aged 50-74, the incidence of grade III tumours in the ASP is significantly lower than in the PSP, but this is not the case for women aged 40-49. This is related to the greater prevalence and rapidity of progression with respect to histologic grade, as evidenced by the results of markov chain models and the proportions of grade III tumours by time since last screen.

CONCLUSIONS

The substantial and significant mortality benefit of invitation to mammographic screening in women aged 40-74 is maintained at 18 years of follow-up. To achieve a substantial mortality benefit at an early stage in the screening program in women aged under 50 years, an interscreening interval of 12-18 months would be required.

A potential complication of laparoscopy--the surgeon's herniated cervical disk

Almost all operations that were traditionally performed by open laparotomy operations can be done laparoscopically; however, surgeons may experience several negative health effects. A 37-year-old gynecologic laparoscopist had a herniated intervertebral disk at C5-6 level. Due to a negative trauma history, a possible explanation may be the nonergonomic posture that he held while performing laparoscopic surgery for many hours. To reduce the risk of this complication, we recommend that surgeons' spatial orientation and hand-eye coordination for laparoscopy be improved by sequential phases of training.

Development of a robotic navigation system for neurosurgery

This paper presents a robotic navigation system for image-guided neurosurgery, which can be applied to the treatment of Parkinson's disease and biopsy of brain tumor. The system integrates a computer for real-time display of brain anatomy, a magnetic tracking device for measuring the positions and orientations of surgical instruments, and a robot manipulator for guiding surgical instruments to the preplanned positions and orientations. The computer display of brain anatomy offers a convenient tool for surgeons to diagnose brain disease and to plan safe surgical paths; while the tracking device assists the robot manipulator to automatically guide surgical instruments to the preplanned direction. The registrations among the tracking device, the image system, and the robot are completed on the base of coordination mappings of external markers. An experiment of using a skull model for simulating a robotic biopsy of brain tumor has been done to verify the performance of the navigation system. The result shows that the system can accomplish a positioning accuracy around 2 mm.

The natriuretic peptides in heart failure: diagnostic and therapeutic potentials

The natriuretic peptides are a group of structurally similar but genetically distinct peptides that have diverse actions in cardiovascular, renal, and endocrine homeostasis. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are of myocardial cell origin and C-type natriuretic peptide (CNP) is of endothelial origin. ANP and BNP bind to the natriuretic peptide-A receptor (NPR-A), which, via 3',5'-cyclic guanosine monophosphate (cGMP), mediates natriuresis, vasodilation, renin inhibition, antimitogenesis, and lusitropic properties. CNP lacks natriuretic actions but possesses vasodilating and growth-inhibiting actions via the guanylyl cyclase-linked natriuretic peptide-B receptor (NPR-B). All three peptides are cleared by the natriuretic peptide-C receptor (NPR-C) and are degraded by the ectoenzyme neutral endopeptidase 24.11 (NEP), both of which are widely expressed in the kidneys, lungs, and the vascular wall. Congestive heart failure (CHF) represents a pathological state in which the activation of the natriuretic peptides exceeds those of all other states. In this brief review, we will attempt to provide an update on important issues regarding natriuretic peptides in CHF, with a focus on their functional importance as a beneficial humoral response in asymptomatic left ventricular dysfunction (LVD), the mechanisms of natriuretic peptide hyporesponsiveness in severe heart failure, the diagnostic and prognostic significance of the natriuretic peptides in CHF, and the therapeutic potential of the natriuretic peptides in this multiorgan syndrome.

Renal actions of synthetic dendroaspis natriuretic peptide

BACKGROUND

Dendroaspis natriuretic peptide (DNP), recently isolated from the venom of the green Mamba snake Dendroaspis angusticeps, is a 38 amino acid peptide containing a 17 amino acid disulfide ring structure similar to that of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). DNP-like immunoreactivity (DNP-LI) was reported to be present in human plasma and atrial myocardium and to be elevated in human congestive heart failure. Although previously named DNP, it remains unknown if DNP is natriuretic or if is it present in canine plasma, urine, and atrial myocardium.

METHOD

Studies were performed in vivo in anesthetized dogs (N = 6) using intravenous infusion of synthetic DNP at 10 and 50 ng/kg/min. Employing a sensitive and specific radioimmunoassay for DNP, the presence of DNP-like peptide was assessed in the canine plasma and urine before, during, and following the administration of exogenous synthetic DNP. Additionally, we performed immunohistochemical studies using the indirect immunoperoxidase method with polyclonal DNP antiserum in normal atrial myocardium (N = 10). Atrial concentrations of DNP-LI were also assessed.

RESULTS

We report that DNP is markedly natriuretic and diuretic, which, like ANP and BNP, is associated with the increase in urinary and plasma cGMP. DNP-like peptide is also detected in canine plasma, urine, and atrial myocardium.

CONCLUSION

These studies establish that DNP is a potent natriuretic and diuretic peptide with tubular actions linked to cGMP and that DNP may play a physiological role in the regulation of sodium excretion.

Development and specification of muscle sensory neurons

Although the response properties and synaptic projections of muscle sensory neurons have been studied extensively, relatively little is known about how these sensory neurons develop their unique phenotypes during embryonic life. The explosion of new information on neurotrophins, however, has revealed that neurotrophin 3 (NT3) is critically involved in several aspects of this development, including the initial differentiation, survival, and perhaps even the terminal arborizations of muscle sensory neurons within the spinal cord. The ETS family of transcription factors, recently shown to be expressed in these sensory neurons, may help specify their choice of synaptic targets in the central nervous system.

Mixed germ cell tumor presenting as intratumoral hemorrhage: report of a case originated from the pineal region

A 17-year-old male patient was brought to our clinic because of sudden onset of headache, vomiting, followed by transient loss of consciousness during a strenuous exercise. Neurologic examinations revealed that the patient had severe sensorimotor and brain stem dysfunction. Examinations of cranial CT and MR imaging showed a huge heterogeneously enhanced tumor originated from the pineal region with tumoral hemorrhage. The tumor markers were found to be high in AFP but not the beta-HCG and CEA. A clinical diagnosis highly suggestive of germ cell tumor was made. Prior to the planned emergency radiation therapy, he received an external ventricular drainage (EVD) and open biopsy of the tumor. Due to a postoperative complication of cerebellar hemorrhage observed 8 hours later, another maneuver was therefore required to extirpate the pineal tumor and cerebellar hematoma. The histological diagnosis proved to be a mixed germ cell tumor with tumoral hemorrhage. Spontaneous intratumoral hemorrhage in germ cell tumor of the pineal region is rare, probably due to compromised venous circulation within the tumor. The bleeding propensity, which may contribute to the formation of cerebellar hematoma, warrants a special attention when a biopsy procedure is to be performed.

Vitamin B6 down-regulates the expression of human GPIIb gene

Glycoprotein IIb (GPIIb) is the alpha-subunit of the platelet membrane receptor GPIIb/IIIa, which plays a major role in platelet aggregation. Vitamin B6 has been reported to be an antiaggregative agent, although its mechanism is not well known. To understand the molecular mechanism of vitamin B6 on antiaggregation, we analyzed the effects of various forms of vitamin B6 on the expression of human GPIIb promoter using chloramphenicol acetyl transferase (CAT) as the reporter gene. The GPIIb promoter region was amplified by polymerase chain reaction (PCR), cloned into pBLCAT3 to drive the CAT reporter gene and transfected into human erythroleukemia (HEL) cells. Transient expression of the GPIIb promoter was determined after transfected cells were treated with 1 microM pyridoxine (PN), pyridoxal (PL), pyridoxal-5-phosphate (PLP), or 4-deoxypyridoxine (4-dex) for 48 h. Our results show that the GPIIb promoter activity was down-regulated to 54, 35 and 63% in the presence of PN, PL and PLP, respectively, as compared to an untreated control whose promoter activity was 100%. However, no adverse effect on GPIIb promoter was detected by 4-dex, which is an antagonist of vitamin B6. The down-regulation effect of vitamin B6 on GPIIb promoter activity may lead to a reduction of GPIIb protein expression and thus be detrimental to platelet aggregation.

Laparoscopic colectomy yields similar morbidity and disability regardless of patient age

This study compared the outcome factors of morbidity and the length of disability in older and younger patients following laparoscopic colorectal surgery. All patients undergoing laparoscopic segmental resection during the study period were included. Morbidity was determined by reviewing the medical records, and disability by a patient-administered questionnaire. The series was divided into two age cohorts (</=64 and >/=65 years), which did not differ significantly in gender or type of procedure. Between these two groups we found no significant differences in mean duration of ileus (3.3 days in both groups), the mean length of hospitalization (5.7 vs. 6.3 days, respectively), morbidity rate (18% vs. 21%), or time until returning to partial activity (1.6 vs. 1.6 weeks) or to full activity (3 vs. 2 weeks). Our findings demonstrate that neither the morbidity rate nor the disability period after laparoscopic techniques differ between elderly and younger patients. We therefore endorse the use of laparoscopy regardless of patient age.

Genotoxic effects of triphenyltin acetate and triphenyltin hydroxide on mammalian cells in vitro and in vivo

Two organotin pesticides, triphenyltin acetate (TPTA) and triphenyltin hydroxide (TPTH), were evaluated for their ability to induce micronuclei (MN) and sister chromatid exchange (SCE) in vitro using cultured Chinese hamster ovary (CHO) cells and in vivo BALB/c mouse erythrocytes. Both pesticides induced a dose-dependent increase but only TPTH induced a significant increase in MN at the highest dose (150 ng/ml) tested in CHO cells. With adding S9 microsomal fractions, both pesticides induced a meaningful MN induction at 150 ng/ml and a dose-dependent significant increase in SCE. In vivo MN induction in erythrocytes was conducted by treating BALB/c mice orally or intraperitoneally with these pesticides either in a single or triple treatments. Oral gavage (p.o.) of TPTA resulted in a dose-related significant increase of MN induction in peripheral blood and of TPTH induced a significant increase in micronucleated reticulocyte (MNRETs) only in a single treatment. Intraperitoneal administration of TPTA or TPTH, however, resulted in meaningless random increases in MN though these increases might be attributable to toxic effects. The MNRETs levels in the treatment with both pesticides were independent to the sampling time. This study demonstrated that TPTA and TPTH was potential chromosome mutagens.

Effect of a microwave coagulator on implanted liver neoplasms in rats

An experimental study was conducted to determine the applicability of a microwave (MW) source for coagulation and dissection of metastatic tumour and liver parenchyma. Twenty PVG rats were studied after implantation of MC28 tumour cells into the liver. Eleven days later they underwent sham laparotomy (control) MW coagulation of the tumour deposit, local resection of the tumour deposit with 2 mm clearance or resection of the tumour with MW coagulation of the resection zone. The control animals all died with blood-stained ascites and heavy tumour burden in the liver. After MW coagulation, tumours disappeared in all but one rat. Local resection also led to tumour clearance in 4 of 5 rats. MW coagulation of the resection zone allowed rapid bloodless resection, and no tumour recurrence was observed after 40-89 days. We conclude that MW coagulation is a potentially useful tool for ablation of hepatic metastasis and as an adjunct to hepatic resection.

Evaluation of screening for nasopharyngeal carcinoma: trial design using Markov chain models

In this paper, we develop a Markov chain model to estimate parameters pertaining to the natural history of nasopharyngeal carcinoma (NPC). The model is of progression from no disease to Epstein-Barr virus (EBV) infection, preclinical screen-detectable tumour and clinical tumour. We derive tentative estimates of the parameters of the model, based on limited published data, to assess the efficacy of serum screening in conjunction with clinical assessment (indirect mirror examination for NPC), for example the average duration of the preclinical screen-detectable phase is estimated as 3.1 years. We further apply these parameters to a hypothetical screening trial in the Hong Kong population to assess the efficacy of serum screening with clinical assessment by different combinations of screening regime. Results suggest: (1) there is no substantial difference between 3-yearly and 6-yearly serum screening; and (2) within the same serum screening regime annual and 3-yearly clinical assessment can prevent 33% and 28% of deaths from NPC respectively. Prediction of deaths and surrogate end points can be used to estimate the required sample size and duration for designing a randomized trial of screening for NPC. Based on these findings and power projections, we suggest a design for a randomized trial in a high incidence area such as Hong Kong.

Microvascular prefabricated free skin flaps for esophageal reconstruction in difficult patients

BACKGROUND

Reconstruction of the esophagus for complicated benign stricture or after resection of malignant lesion is still a challenge for surgeons. When abdominal viscera cannot be used, skin flaps are selected for esophageal reconstruction. However, skin flaps for esophageal reconstruction are notorious for leakage, and have not been widely accepted. Prefabrication before microvascular transfer to its final site can improve the result of esophageal reconstruction when skin flaps are used.

METHODS

Eight patients with complicated corrosive esophagitis had been treated with prefabricated skin flaps for esophageal reconstruction. The procedures are described in detail.

RESULTS

All patients healed well without leakage. The barium study showed smooth passage. There was no dysphasia or regurgitation after education. Pulmonary complication happened in only 1 patient. Revision for the distal anastomosis was required in 1 patient due to narrowing. When the skin tube is long, the patients need water (or soup) to facilitate swallowing and occasionally use their hand to help the food passage. This method has the following advantages: (1) healing of the long suture line before transfer to withstand the intestinal juice; (2) reliable viability in the distal part of the flap, especially when an extended length of the flap is required; (3) more length of stable tissue for two-layered, tension-free anastomosis at the junction of skin and gastrointestinal mucosa to prevent leakage; and (4) the flap can be placed in the substernal position to meet the aesthetic requirement of young patients. The disadvantage was the staged operations. However, after prefabrication the transfer becomes safe and free of leakage. The overall morbidity is minimal.

CONCLUSIONS

In rare situations when skin flaps are used for esophageal reconstruction, prefabrication provides advantages over conventional one-stage methods, although it needs additional procedures. This method is a combination of conventional technique and microsurgery.

Effects of chronic lead (Pb) exposure on neurobehavioral function and dopaminergic neurotransmitter receptors in rats

Sprague-Dawley rats were maternally and permanently exposed to Pb (1000 ppm in their drinking water as lead acetate). Behavioral functions were examined starting at post-natal day (PN) 84. Lead exposure did not change spatial learning in the radial arm maze, but induced higher locomotor activity as observed in the open-field and in the radial arm maze. Lead treatment did not impact motor coordination. Autoradiographic analysis of brain sections indicated that Pb-exposure did produce a decrease in [125I]sulpride (D2 receptor antagonist) binding in the cerebral cortex, but not in the striatum and thalamus nucleus. No change was found in [125I]SCH-23982 (D1 receptor antagonist) binding. Since the cortical dopaminergic system is critical for cognitive processes and motor behavior, it is possible that Pb-related change in D2 receptors may mediate to it induced hyperlocomotor activity.

Influences of walking speed change on the lumbosacral joint force distribution

To more understand the influence of the walking speed on the spinal joint force distribution, a three-dimensional biomechanical model was used to estimate the spine loads during human gait with three different walking speeds. This previously developed and validated model included a dynamic external model and an internal model with forces of disc, 8 major muscles, 2 ligaments and 2 facet joints at L5/S1 level. A linear optimization method was used to solve the internal model to estimate the L5/S1 spinal joint force distribution. The results of five young male subjects showed that the mean peak L5/S1 disc compressive forces on the slow, preferred and fast speeds were 2.28, 2.53, 2.95 body weight, respectively. The peak forces happened right after the heel strike and before completely toe off. The facet joint forces were generally increased with the walking speed increase, too. To reduce the loads on the spine, the slow walking is then recommended for the patients with low back pain or after spinal surgery.

Anal manometric findings before and after hemorrhoidectomy: a preliminary report

BACKGROUND

A difference of opinion exists as to whether patients with symptomatic hemorrhoids, patients after hemorrhoidectomy, and patients with no hemorrhoids have different anal physiologies.

METHODS

Twenty-four patients with symptomatic hemorrhoids undergoing hemorrhoidectomy were investigated using anorectal manometry. There were 12 male and 12 female patients with a mean age of 42 years (range: 23 to 72 years). The anorectal manometry was performed one day before the operation and 8 to 12 weeks after the operation. Another normal group, comprised of 138 volunteers, was included and matched for age and gender.

RESULTS

The anorectal inhibitory reflex was present in all the normal group (NG), symptomatic hemorrhoid (SH), and post-hemorrhoidectomy (PH) patients. No major incontinence was noted clinically. The mean resting pressure (MRP) in the SH group (mean: 84.5 +/- 28.7 cmH2O, range: 26 to 166 cmH2O) was significantly greater than in the NG (mean: 74.4 +/- 14.9 cmH2O, range: 61 to 116 cmH2O) and the PH groups (mean: 63.7 +/- 23.6 cmH2O, range: 20 to 116 cmH2O) (p = 0.032 and 0.005, respectively). After hemorrhoidectomy, the MRP was significantly decreased compared to the normal group (p = 0.018). The other manometric data showed no statistical change in these three groups.

CONCLUSION

The results indicate that persons with SH have a higher MRP than normal. Overactivity of the internal sphincter muscle may be a cause rather than a result of symptomatic hemorrhoids. Compared with the SH and normal groups, the MRP was significantly decreased to prevent recurrent symptomatic hemorrhoids in the PH group. Though the MRP was significantly decreased, no major incontinence was noted after hemorrhoidectomy, and this might be due to the increase in rectal compliance and mean squeeze pressure.

Microvascular vastus lateralis muscle flap for chronic empyema associated with a large cavity

Thoracic empyema can be disabling and may need microvascular free flaps in some intractable cases. After repeated failure of conventional thoracic surgical procedures, 2 patients with empyema were treated with microvascular free vastus lateralis muscle flaps for obliteration of the large empyema cavity. The reconstruction was successful in wound closure and eradication of infection. The donor site morbidity was minimal, and the patients resumed normal daily activities. Microvascular vastus lateralis muscle flap is the best option if free flaps are required for reconstruction of empyema.

Protein kinase C in rat brain is altered by developmental lead exposure

The absence of learning-related redistribution of hippocampal protein kinase C (PKC) has been correlated with impairment of learning performance induced by developmental lead (Pb) exposure. This study was designed to examine whether the properties of brain PKC are altered by chronic Pb exposure during development. Two-tenth percent Pb acetate was administered to pregnant and lactating dams and then administered to weanlings in drinking water until postnatal day (PN) 56. Effects of Pb on translocation of PKC were studied in brain slices prepared from hippocampus. When the slices were treated with 0.33 microM phorbol-12, 13-dibutyrate (PDBu) for 15 min, a significant increase in PKC activity was observed in the membrane fraction of hippocampal slices from Pb-exposed rats, suggesting that chronic Pb exposure potentiates PDBu-activated PKC translocation. Data obtained from saturation binding assays in the frontal cortices of Pb-exposed rats showed a decrease in the dissociation constant (KD) in both membrane and cytosolic PKC. A decrease in the total binding sites (Bmax) of [3H]PDBu binding was only observed in membrane PKC. Furthermore, developmental Pb exposure decreased PKC-gamma, but not PKC-alpha, -betaII, and -epsilon in the membrane fraction of the hippocampus and the frontal cortex. These results indicate that chronic Pb exposure during development increases phorbol ester binding affinity, enhances phorbol ester-induced translocation of PKC, and down-regulates membrane PKC, mainly PKC-gamma.

DNA from both high-capacity and first-generation adenoviral vectors remains intact in skeletal muscle

Previous studies of the use of adenoviral vectors in animal models of gene therapy have focused on the immune response against transduced cells as the major limiting factor to long-term transgene expression. In this study we eliminated the variable of immunity induced by expression of the transgene in order to investigate vector DNA stability of both first-generation and high-capacity adenoviral vectors after gene transfer to skeletal muscle. Transgene expression from a high-capacity adenoviral vector remained at a high level for at least 20 weeks and was accompanied by persistence of intact vector genomes. In contrast, transgene expression from a first-generation adenoviral vector markedly diminished by 6 weeks after gene transfer and was accompanied by mild and variable inflammatory cell infiltrates. Surprisingly, despite this loss of transgene expression, the first-generation adenoviral vector genomes persisted like the high-capacity adenoviral vector genomes. Therefore, in the absence of immunity to transgene proteins, loss of expression from the first-generation vector was due to inhibition of transgene expression rather than to the elimination of vector-containing cells. DNA stability and persistent expression of the high-capacity adenoviral vector supports the potential of this vector for clinical applications of muscle gene transfer.

Presence of Dendroaspis natriuretic peptide-like immunoreactivity in human plasma and its increase during human heart failure

OBJECTIVE

To determine whether Dendroaspis natriuretic peptide (DNP), a novel peptide isolated from the venom of the Dendroaspis angusticeps snake that contains a 17-amino acid disulfide ring structure similar to that in atrial, brain, and C-type natriuretic peptides, is present in normal human plasma and myocardium and whether, like the other natriuretic peptides, DNP-like immunoreactivity (DNP-LI) is activated in human congestive heart failure (CHF).

MATERIAL AND METHODS

Circulating DNP-LI was assessed in 19 normal human subjects and 19 patients with CHF (New York Heart Association class III or IV) with a specific and sensitive radioimmunoassay for DNP with no cross-reactivity with the other natriuretic peptides. Immunohistochemical studies that used polyclonal rabbit anti-DNP antiserum were performed on human atrial myocardial tissue obtained from four patients with end-stage CHF who were undergoing cardiac transplantation and from three donor hearts at the time of transplantation.

RESULTS

We report that DNP-LI circulates in normal human plasma and is present in the normal atrial myocardium. In addition, DNP-LI is increased in the plasma of patients with CHF.

CONCLUSION

This study demonstrates, for the first time, the presence of a DNP-like peptide in normal human plasma and in the atrial myocardium. Additionally, these studies demonstrate increased plasma DNP-LI in human CHF. These results support the possible existence of an additional new natriuretic peptide in humans, which may have a role in the neurohumoral activation that characterizes human CHF.

Regional thrombolysis with urokinase for central venous catheter-related thrombosis in patients undergoing high-dose chemotherapy with autologous blood stem cell rescue

Fifty-one of 300 patients undergoing high-dose chemotherapy with (n = 245) or without (n = 55) autologous stem cell rescue developed central venous catheter-related thrombosis diagnosed by Doppler sonography or contrast venography. Eighteen of these individuals underwent regional thrombolysis defined as the infusion of urokinase into a superficial vein of the ipsilateral upper extremity in a dose not sufficient to produce systemic fibrinolysis by laboratory criteria. Urokinase was administered at a dose of 75,000-150,000 U/hour for 24 to 96 hours and contrast venography was performed to assess response. All individuals had a partial or complete resolution of clinical signs and symptoms. Fifty percent of patients also achieved a partial radiographic response defined as clot lysis with irregular canalization of the vein. Therapeutic doses of heparin for 5 to 7 days and warfarin for at least 3 months were commenced at the conclusion of urokinase therapy. Twelve catheters were salvaged and utilized subsequently until no longer required. Six catheters were removed because of poor catheter function or rethrombosis. The median interval from diagnosis of the thrombus until extraction of the 12 salvaged catheters was 3 months (range 1-8 months). Only a single patient who developed gastrointestinal bleeding required discontinuation of urokinase. Regional thrombolysis is safe, easy to administer, effective in many instances, less costly than the doses of antifibrinolytic agents required to induce systemic fibrinolysis, and should be considered in patients receiving high-dose chemotherapy with autologous stem cell rescue who develop central venous catheter-related thrombosis.

Structural analysis of inhibitor binding to human carbonic anhydrase II

X-ray crystal structures of carbonic anhydrase II (CAII) complexed with sulfonamide inhibitors illuminate the structural determinants of high affinity binding in the nanomolar regime. The primary binding interaction is the coordination of a primary sulfonamide group to the active site zinc ion. Secondary interactions fine-tune tight binding in regions of the active site cavity >5 A away from zinc, and this work highlights three such features: (1) advantageous conformational restraints of a bicyclic thienothiazene-6-sulfonamide-1,1-dioxide inhibitor skeleton in comparison with a monocyclic 2,5-thiophenedisulfonamide skeleton; (2) optimal substituents attached to a secondary sulfonamide group targeted to interact with hydrophobic patches defined by Phe131, Leu198, and Pro202; and (3) optimal stereochemistry and configuration at the C-4 position of bicyclic thienothiazene-6-sulfonamides; the C-4 substituent can interact with His64, the catalytic proton shuttle. Structure-activity relationships rationalize affinity trends observed during the development of brinzolamide (Azopt), the newest carbonic anhydrase inhibitor approved for the treatment of glaucoma.

Laparoscopic colectomy for benign colorectal disease is associated with a significant reduction in disability as compared with laparotomy

BACKGROUND

The aim of this study was to evaluate disability after laparoscopic colectomy in patients with benign colorectal disease.

METHODS

Patients who underwent laparoscopic colectomy for benign colorectal diseases were matched with patients who underwent laparotomy for the same diseases by the same surgeons during the same time period. A standardized questionnaire used to assess disability included days until return to partial activity, full activity, and work.

RESULTS

Seventy-one patients who underwent laparotomy were compared with 71 patients who underwent laparoscopy. Pathology included 26 patients with adenoma, 23 with Crohn's disease, 13 with diverticulitis, and 9 with reversal of Hartmann's procedure in each group. Procedures were partial colectomy with ileocolostomy, colocolostomy, or colorectostomy. There were no significant differences (p > 0.05) in age (55.8 vs. 59.7 years) or in the incidence of perioperative complications (25% vs. 29%) between the laparoscopy and laparotomy groups, respectively. The operative time was longer in the laparoscopic group than in the laparotomy group: 165 versus 122 min (p < 0.001). However, length of hospitalization, return to partial and full activity, and time off of work were significantly shorter in the laparoscopy than in the laparotomy group: 6.3 versus 9.0 days, 2.1 versus 4.4 weeks, 4.2 versus 10.5 weeks and 3.8 versus 7.5 weeks, respectively (p < 0.01 for all).

CONCLUSIONS

Laparoscopic colectomy for benign colorectal diseases was associated with significantly less disability than was laparotomy in terms of length of hospitalization as well as return to baseline partial and full activity and employment.