Adipose derived mesenchymal stem cell secretome formulation as a biotherapeutic to inhibit growth of drug resistant triple negative breast cancer

In the present study, a protocol was developed for processing of human adipose derived mesenchymal stem cell secretome formulation of varying concentration. Its molecular composition was evaluated, and its effectiveness in vitro using breast cancer cell lines, and in vivo in a nude mice breast cancer model was studied to determine its role in suppressing triple negative breast cancer in a dose dependent manner. Because the secretome could have value as an add-on therapy along with a current drug, the effectiveness of the secretome both in monotherapy and in combination therapy along with paclitaxel was evaluated. The results showed significant cell kill when exposed to the secretome above 20 mg/ml at which concentration there was no toxicity to normal cells. 70 mg/ml of SF showed 90 ± 10% apoptosis and significant decrease in CD44⁺/CD24⁻, MDR1+ and PDL-1+ cancer cells. In vivo, the tumor showed no growth after daily intra tumor injections at 50 mg/ml and 100 mg/ml doses whereas substantial tumor growth occurred after saline intra tumor injection. The study concludes that SF is a potential biotherapeutic for breast cancer and could be used initially as an add-on therapy to other standard of care to provide improved efficacy without other adverse effects.

Reversible ventricular dysfunction in cyanotic heart disease

Ventricular dysfunction is a matter of concern for any preoperative cardiac patient. We describe 2 cases of cyanotic congenital heart disease (CCHD) awaiting on pump repair with hypoxia as a cause of ventricular dysfunction. Any Cyanotic Congenital heart disease presenting with ventricular dysfunction should be evaluated for treatable causes like hypoxia after exclusion of structural causes for the same.

Lutembacher syndrome with unroofed left superior vena cava: a diagnostic dilemma

Lutembacher syndrome involving the association of congenital atrial septal defect (ASD), usually of the ostium secundum variety, and mitral valve disease is a well-known entity. Its association with a coronary sinus, ASD, and a persistent left superior vena cava (LSVC) draining into the left atrium (LA) (Raghib syndrome) is rarely described in the literature. This association in a 15-year-old boy erroneously deemed to be inoperable before referral to the authors' hospital due to cyanosis in the presence of atrial septal defect (ASD) and mitral stenosis is described in this report. Evaluation by echocardiography followed by cine angiography confirmed the cause of cyanosis to be drainage of the LSVC into the LA together with an ASD and rheumatic mitral stenosis, a combination of Raghib and Lutembacher syndromes. The boy underwent successful surgical correction. The authors believe this is the second such case to be reported in the English literature and the first of its kind to be managed by surgical intervention.

Combined Bentall and modified Ravitch procedures in a patient with Marfan syndrome

Marfan syndrome is an inherited, connective-tissue disorder transmitted as an autosomal dominant trait. Cardinal features of the disorder include tall stature, ectopia lentis, mitral valve prolapse, aortic root dilatation, and aortic dissection. Pectus excavatum may exist as an isolated lesion or in association with a genetic syndrome such as Marfan syndrome. We report the successful management of a simultaneous correction of pectus excavatum and the underlying cardiovascular diseases.

Symptomatic giant left atrial aneurysm in a child: a rare entity

Isolated left atrial aneurysms are rare entities in clinical practice. Usually the condition is diagnosed in the second to fourth decades of life. The presence of such lesions in the pediatric age group is scantily described. We present a 2 year boy who presented with complaints of excessive irritability, respiratory distress and swelling of the feet. On examination, child was tachypnoeic with irregularly irregular rhythm. Echo showed a huge aneurysmal LA appendage with severe left ventricle dysfunction. The child underwent surgical resection for same. Findings were confirmed intraoperatively but he continued to have low cardiac output state after the surgery, with frequent arrhythmias and expired on day 7 of surgery. The case is reviewed and compared with the available English literature.

Unusual case of ruptured sinus of Valsalva: rupture into left ventricle cavity along with distortion of mitral valve requiring double valve replacement

We report a rare case of sinus of Valsalva aneurysm of left aortic sinus, which was bulging into left atrium (LA) distorting mitral valve and rupture into the left ventricle with severe aortic regurgitation in a 25 years old male patient. Due to the rupture, both aortic and mitral valves were irreparable and required a double valve replacement along with the closure of the neck of the aneurysmal cavity occupying the left atrial roof.

Identification of the structural and functional determinants of the extracellular domain of the human follicle stimulating hormone receptor

The extracellular domain (ECD) of the human follicle-stimulating hormone receptor (hFSHR) is believed to be the major determinant of hormone selectivity. Different discrete, discontinuous regions on the ECD of the hFSHR have been suggested to be crucial for hormone binding. However, the role of the ECD in signal transduction is not well understood. This study provides some insight into these aspects of the structure-function relationship of the ECD of hFSHR. Ten peptides were selected from the ECD on the basis of their ability to be surface oriented, synthesized by the solid-phase method using fluorenylmethyloxycarbonyl chemistry, purified and characterized. They were further studied for their ability to modulate both human follicle-stimulating hormone (hFSH)-FSHR binding and cAMP generation. Competitive inhibition studies showed that, of all the peptides studied, peptides 285-300 and 297-310 hFSHR were able to inhibit hFSH binding to FSHR. Both peptides function as weak competitive inhibitors of hFSH-FSHR binding. Peptides 285-300 hFSHR, 216-235 hFSHR, 184-195 hFSHR, 79-89 hFSHR and 15-31 hFSHR were observed to inhibit FSH-induced cAMP production. In summary, this study suggests that discrete, functional domains of the ECD have a role in hormone binding and signal transduction. Region 285-300 has been identified as a novel region crucial for both FSH binding and cAMP generation.

Attempt to map the receptor binding sites of human follicle-stimulating hormone using disulfide peptides of its beta-subunit indicates major involvement of the regions around disulfide bonds Cys28-Cys82 and Cys32-Cys84 in receptor binding of the hormone

Follicle-stimulating hormone (FSH) is a heterodimeric glycoprotein hormone secreted by the anterior pituitary. It plays a very important role in folliculogenesis in females and is responsible for spermatogenesis in males. The alpha-subunit which is common within a species and the beta-subunit which is hormone-specific are held together by noncovalent association. This association is very essential for the biological activity of the hormone. Each of these subunits are highly cross-linked by disulfide bonds which appear to stabilize the tertiary structures required for the noncovalent association of the subunits to generate hormonal activity. This study was initiated to delineate the role of the disulfide bonds of hFSH beta in receptor binding of the hormone. Five intermolecular and one intramolecular disulfide peptides corresponding to the disulfide bonds found in hFSH beta were synthesized and screened along with their linear counterparts, for their ability to competitively inhibit the radiolabelled [125I]hFSH from binding to the FSH receptor containing membranes from the testis of immature rats. The disulfide peptides Cys28-Cys82 and Cys32-Cys84 were found to be the most potent in inhibiting radiolabelled hFSH from binding to its receptor. The results suggest the involvement of the regions around disulfide bonds Cys28-Cys82 and Cys32-Cys84 in receptor binding of the hormone. The studies also suggest the involvement of beta L2 and beta L3 loop regions in receptor binding of the hormone. This study is the first of its kind to use disulfide peptides rather than linear peptides to map the receptor binding regions of hFSH.

Disulfide bonds Cys(9)-Cys(57), Cys(34)-Cys(88) and Cys(38)-Cys(90) of the beta-subunit of human chorionic gonadotropin are crucial for heterodimer formation with the alpha-subunit: experimental evidence for the conclusions from the crystal structure of hCG

Human chorionic gonadotropin (hCG) is a heterodimeric glycoprotein hormone essential for the establishment and maintenance of pregnancy. The alpha- and beta-subunits of hCG are highly cross-linked internally by disulfide bonds that seem to stabilize the tertiary structures required for the noncovalent association of the subunits to generate hormonal activity. This paper describes the results of our studies on the role of the disulfide bonds of hCG-beta in heterodimer formation with the alpha-subunit. Six disulfide peptides incorporating each of the six disulfide bonds of hCG-beta were screened, along with their linear counterparts, for their ability to competitively inhibit the recombination of alpha- and beta-subunits. The disulfide peptides Cys (9-57), Cys (34-88) and Cys (38-90) were found to inhibit the alpha/beta recombination whereas the remaining three disulfide peptides viz. Cys (23-72), Cys (26-110) and Cys (93-100) did not exhibit any inhibition activity. Interestingly, none of the linear peptides could inhibit the alpha/beta recombination. Results clearly demonstrate that the disulfide bonds Cys(9)-Cys(57), Cys(34)-Cys(88) and Cys(38)-Cys(90) of the beta-subunit of hCG are crucial for heterodimer formation with the alpha-subunit thus providing experimental confirmation of the conclusions from the crystal structure of the hormone.

Effect of active immunization with the C-terminal 67-94 (R-28) region of human seminal plasma inhibin on the fecundity of adult male rabbits

PROBLEM

To characterize the specificity of antibodies to the synthetic C-terminal 67-94 (R-28) peptide of human seminal plasma inhibin (hSPI), and to examine the effect of active immunization on the fecundity of adult male animals.

METHOD OF STUDY

The specificity of R-28-DT antibodies was tested using enzyme-linked immunosorbent assay, immunohistochemical and immunofluorescence staining, and Western blotting. For fertility studies, adult male rats and rabbits were immunized and mated with females of the same strain.

RESULTS

Rabbit antibodies to R-28-DT recognized native hSPI, as demonstrated by sperm agglutination in vivo and in vitro, on the sperm head by immunofluorescence staining, and in the columnar epithelial cells of the prostate by immunohistochemical staining. Immunization with the R-28-DT conjugate elicited a poor antibody response in male rats and their fecundity remained unaffected, while in male rabbits it elicited a good immune response with reduction in their fertility.

CONCLUSION

R-28-DT antibodies recognized the native hSPI in the prostatic epithelium and agglutinated washed rat, rabbit, monkey, and human spermatozoa in vitro. Immunization of rabbits caused agglutination of spermatozoa resulting in a decrease in their fecundity. The conjugated R-28 peptide of hSPI offers promise as a male contraceptive.

A detailed study of the L2beta long-loop region of human chorionic gonadotrophin suggests it to be spatially close to, but not part of, the receptor-binding site

An in-depth study of the L2beta long-loop region of human chorionic gonadotrophin (hCG), earlier identified to be a conformational bioneutralization epitope and receptor-binding site of the hormone, was carried out. The linear 38-57 hCGbeta peptide and the corresponding cyclic disulphide peptide were synthesized and antipeptide antibodies developed. Binding studies with antibodies to the linear peptide, and with hCGbeta, hCG and human LH suggest that part of the region is buried at the alpha/beta interface and part exposed in hCG. Observation of the surface exposure of residues 47-53 from the crystal structure of hCG was confirmed by epitope mapping studies of the region. The region is not unique to hCG as a majority of the antibodies to both the linear and cyclic peptides did not exhibit the required specificity. Competitive inhibition studies with the linear and cyclic peptides failed to show inhibition of radiolabelled hCG binding to its receptors. However, both the antipeptide antibodies were able to bioneutralize the hormone in an in vivo assay. Taken together, these results seem to indicate that the L2beta long-loop region is not a receptor-binding site of hCG but spatially close to it.

Mapping the receptor binding regions of human chorionic gonadotropin (hCG) using disulfide peptides of its beta-subunit: possible involvement of the disulfide bonds Cys(9)-Cys(57) and Cys(23)-Cys(72) in receptor binding of the hormone

Human chorionic gonadotropin (hCG) is a heterodimeric glycoprotein hormone essential for the establishment and maintenance of pregnancy. The alpha- and beta-subunits of hCG are highly cross-linked internally by disulfide bonds which seem to stabilize the tertiary structures required for the noncovalent association of the subunits to generate hormonal activity. The purpose of this study was to delineate the role of the disulfide bonds of hCGbeta in receptor binding of the hormone. Six disulfide peptides incorporating each of the six disulfide bonds of hCGbeta were synthesized and screened, along with their linear counterparts, for their ability to competitively inhibit the binding of [125I] hCG to sheep ovarian corpora luteal LH/CG receptor. Disulfide peptide Cys (9-57) was found to be approximately 4-fold more potent than the most active of its linear counterparts in inhibiting radiolabeled hCG from binding to its receptor. Similarly, disulfide peptide Cys (23-72) exhibited receptor binding inhibition activity, whereas the constituent linear peptides were found to be inactive. The results suggest the involvement of the disulfide bonds Cys(9)-Cys(57) and Cys(23)-Cys(72) of the beta-subunit of hCG in receptor binding of the hormone. This study is the first of its kind to use disulfide peptides rather than linear peptides to map the receptor binding regions of hCG.

Constraints in the development of contraceptives for men

Considerable efforts have been made to develop a male contraceptive and the studies have provided very useful information in this field. At least five different strategies to develop a male contraceptive have been pursued, namely: inhibition of sperm production, interference with sperm function, interruption of sperm transport, prevention of sperm deposition, and prevention of sperm-egg interaction. Of all these approaches, inhibition of sperm production by using androgens either alone or in combination with progestins have given the most encouraging results. A number of clinical trials substantiate that it is indeed possible to have a reversible, effective and safe hormonal method of contraception. A postmeiotic and epididymal approach to interfere with sperm function or the secretory and metabolic processes of the epididymis is another attractive option of male contraceptive development. A number of chemical compounds have been identified which interfere with sperm function in the epididymis without affecting sperm production, however, the compounds evaluated so far were found to be toxic. Interruption of sperm transport through the vas either by vasectomy or percutaneous intravasal injection of liquids which form cure-in-place plugs is also an attractive option. However, reversibility of the methods is of concern in their wide scale use. The major constraint in developing a long-acting male contraceptive seems to be the need for greater investment for product development. The clinical trials for evaluating the efficacy and safety of the new products and formulations stretch over several years and require enormous financial commitment. Nevertheless, the long-term gain of having a long-acting reversible contraceptive for men is far greater than the financial commitments over few years. Male attitude towards using methods of family planning is much more favourable than originally believed. The pharmaceutical industry as well as the health care providers therefore have a greater responsibility. For early development of a contraceptive for men, it is essential to increase investment and simplify the drug regulatory procedures. The advent of newer technologies coupled with the convergent efforts of scientists will certainly make it possible to have an effective, safe and reversible male contraceptive in the near future.

Effect of immunization with synthetic peptide corresponding to region 1-17 of human seminal plasma inhibin on fertility of male rats

Immunization of adult male rats with a synthetic peptide corresponding to the region 1-17 of human seminal plasma inhibin (hSPI) resulted in agglutination of epididymal sperm, severely affecting the fertility of the animals (75% reduction in fertility as compared to control). This effect was found to be dependent on the antibody titer to hSPI. There was a significant rise in circulating follicle-stimulating hormone levels, with luteinizing hormone and testosterone levels remaining unaffected. The histology of the testes and other reproductive organs revealed that these organs remained unaltered. The N-terminal 1-17 amino acid peptide of hSPI may hold promise as an immunogen for male immunocontraception.

Significant intraoperative right ventricular outflow gradients after repair for tetralogy of Fallot: to revise or not to revise?

BACKGROUND

This study was performed to define alternative parameters for the management of intraoperative residual right ventricular outflow obstruction (RVOTO) after transatrial repair of tetralogy of Fallot (ToF) in order to differentiate those requiring immediate revision from those who do not.

METHODS

Since October 1995, 166 patients of ToF underwent transatrial repair. Postbypass residual RVOTO was assessed by surgeon's subjective impression, direct intracardiac pressure measurements, and intraoperative echocardiography (IOE). RVOTO was labeled "significant" whenever it exceeded a gradient of 40 mm Hg on IOE or right ventricular to left ventricular pressure ratio (pRV/LV) exceeded 0.85. Further, on IOE, significant RVOTO was defined "fixed", if there was no change in RVOT dimensions during the cardiac cycle, along with the presence of anatomic substrate for obstruction, and "dynamic" if RVOT dimensions increased appreciably in diastole. Postoperative course and follow-up echocardiograms of all patients were analyzed.

RESULTS

Significant RVOTO was detected in 58 (35%) patients (mean gradient 54 mm Hg). Seven (12%) of them with fixed obstruction (mean 46 mm Hg) underwent immediate surgical revision, while the remaining 51 patients with mean gradient of 78 mm Hg (including 10 patients with pRV/LV ratio of > or = 1.0) with dynamic obstruction did not undergo revision. There were six (3.6%) early deaths. Operative mortality and postoperative morbidity were not related to higher residual gradients, although the first 15 such patients had longer intensive care stay and inotropic support, in which this was done electively. On follow-up (mean 18.5 months), outflow gradients declined sharply (mean 16 mm Hg) irrespective of the severity of intraoperative gradients (p < 0.001). There were no reoperations or late deaths.

CONCLUSIONS

This study shows that: 1) existing parameters for immediate revision of residual RVOTO possibly need to be reviewed; 2) intraoperative echocardiography helps in differentiating "fixed" from "dynamic" obstruction and helps obviate needless revisions; and 3) dynamic RVOT gradients decline significantly irrespective of their severity after transatrial repair of ToF.

Sevoflurane for induction and intubation in children undergoing congenital cardiac surgery

The induction and intubation characteristics of sevoflurane were studied prospectively in 23 children, aged 3 months to 6 years (mean 24 +/- 20.25), undergoing repair of congenital cardiac defects. After premedication with syrup chloral hydrate (75mg/kg orally), anaesthesia was induced with 8% sevoflurane and 50% nitrous oxide in oxygen. Nasal endotracheal intubation was performed once the pupils were small and central, without the use of neuromuscular blocking agents or opioids. Characteristics of induction and intubating conditions were recorded. Induction time (from application of face mask to loss of eyelash reflex) was 43.7 +/- 4.57 secs (mean +/- SD). Mean intubation time was 149.1 +/- 15.6 secs. Intubating conditions were excellent in 21 patients (91.3%) and good in 2 patients (80.7%). Haemodynamic parameters (heart rate, rhythm, and systolic blood pressure) were recorded at loss of eyelash reflex, immediately before intubation and at 1, 3 and 5 min after intubation. All children remained haemodynamically stable throughout induction and there were no adverse airway events.

Isolation and purification of an early pregnancy factor-like molecule from culture supernatants obtained from lymphocytes of pregnant women

PURPOSE

Our purpose was to determine whether lymphocytes synthesize proteins during pregnancy, to observe whether one of the proteins synthesized has early pregnancy factor (EPF)-like activity and to isolate and purify this molecule from culture supernatants obtained from stimulated lymphocytes of pregnant women.

METHODS

Lymphocyte proliferation assay and 35S-methionine labeling were done to study de novo synthesis of proteins followed by autoradiography to confirm synthesis of proteins. The rosette inhibition assay was used for detection of the EPF-like molecule. Gel filtration on Sephadex G-100 and RPHPLC were used for purification of the EPF-like molecule.

RESULTS

The rate of incorporation of 35S-methionine was significantly higher in the lymphocytes of pregnant women compared to those of the control, and autoradiography confirmed the synthesis of proteins during pregnancy. There is a total protein enhancement trend observed during the first trimester that declines toward term. The EPF-like molecule is observed to be synthesized during all the trimesters of pregnancy. This molecule, when purified, showed a single homogeneous biologically active peak.

CONCLUSIONS

The results indicated that there is an enhancement of existing protein or synthesis of new proteins during pregnancy. The EPF-like molecule is one of the many proteins synthesized and secreted by lymphocytes during pregnancy that, when purified, is biologically active.

Intraoperative echocardiography as a routine adjunct in assessing repair of congenital heart defects: experience with 300 cases

Utility of intraoperative echocardiography (IOE) in perioperative management of congenital heart disease has been reported in literature. However, its consistent use as a monitoring tool has not yet been reported from our country. The aim of this study was to evaluate the role of routine use of IOE for intraoperative assessment of surgical repairs in terms of residual shunt, residual gradient, valvular insufficiency and ventricular function. Three hundred consecutive patients above 3 Kg body weight were included in this study. In 152 patients epicardial and in 148 patients transoesophageal echocardiography (TEE) was performed intraoperatively. Age ranged from 4 months to 52 years (median 5.8 yrs) and body weight from 3 Kg to 62 Kg (Median 12 Kg). IOE Doppler and Doppler colour flow imaging studies were performed before cardiopulmonary bypass (CPB) whenever feasible and after CPB in all patients. Pre-bypass examination yielded additional information in 17 (5.6%) patients. In 9 (3%) such patients it had an impact on surgery. In post CPB IOE studies, surgery was found to be 'perfect' in 210 (70%) patients and 'acceptable' residual defects in 70 (23.3%) patients. In 20 (6.6%) cases post CPB IOE found surgical repair 'unacceptable'. Ten of these patients required immediate surgical revision with excellent outcome, thus saving them from late reoperation or postoperative complications. No short term complications were encountered relating to the procedure. We conclude that intraoperative echocardiography is an inexpensive, accurate, valuable and safe addition to the perioperative care of patients and should be mandatory during all corrective surgical procedures for congenital heart disease. It is especially applicable in our country where the costs of reoperation for residual defects are prohibitive.

Identification of bioneutralization epitopes of human follicle stimulating hormone in the regions 31-52 and 66-75 of its beta-subunit

The crucial role played by follicle stimulating hormone (FSH) in regulating both male and female reproduction and the possibilities of developing contraceptive methods for males by blocking the function of the hormone, makes it important to delineate the hormone-specific bioneutralization epitopes of human follicle stimulating hormone (hFSH) on its beta-subunit. Predictive methods were used to identify the potential surface-oriented regions of hFSH-beta. Peptides corresponding to these regions, i.e. 31-52, 66-75 and 86-95 hFSH-beta, were synthesized, anti-peptide antibodies were elicited in rabbits and the properties of these antisera to bind hFSH and neutralize its biological activity were assessed. Anti-31-52 hFSH-beta antisera bound hFSH specifically, whereas anti-66-75 and anti-86-95 hFSH-beta antisera did not show any detectable binding, proving the region 31-52 hFSH-beta to be a specific antigenic determinant of hFSH. The bioneutralizing abilities of the anti-peptide antibodies were assessed by measuring the hFSH-induced progesterone secretion by rat granulosa cells in vitro. Antibodies to 31-52 and 66-75 hFSH-beta neutralized the bioactivity of hFSH, but anti-86-95 hFSH-beta antibodies did not. Furthermore, the three linear peptides and two disulphide looped peptides of 31-52 hFSH-beta and 86-95 hFSH-beta were also subjected to the in-vitro granulosa cell assay. The linear peptides 31-52 hFSH-beta and 66-75 hFSH-beta and the cyclic 31-52 hFSH-beta disulphide loop peptide significantly inhibited the hFSH-induced progesterone secretion by rat granulosa cells, but the linear 86-95 hFSH-beta peptide and the corresponding cyclic disulphide loop peptide did not. The results clearly show that the regions 31-52 and 66-75 of hFSH-beta harbor bioneutralization epitopes of the hormone. The studies also indicate that cyclization of the linear 31-52 hFSH-beta peptide greatly enhances receptor recognition and that the region 66-75 hFSH-beta may also be involved in hormone-receptor interaction.

Right ventricle to pulmonary artery connections

From March 1988 through June 1995, 80 patients underwent repair for right ventricle (RV) to pulmonary artery (PA) discontinuity. Of these, 30 patients received homograft conduits, while the remaining 50 underwent repair without the use of a homograft. Handmade pericardial valved vascutek conduits (n = 18), non-valved vascutek tubes (n = 13) and non-conduit procedures like the rev operation (n = 12) and extended pericardial gusset (n = 5) were mainly used. The indications for repair for RV-PA discontinuity included ventricular septal defect with pulmonary atresia (VSD PA) (n = 36), truncus arteriosus (n = 18), ventricular septal defect with pulmonary and major aorto-pulmonary collaterals (VSD PA MAPCA) with staged repair (n = 5), congenitally corrected transposition of the great arteries with ventricular septal defect and pulmonic stenosis (CCTGA VSD PS) (n = 5) and double outlet left ventricle with ventricular septal defect and pulmonic stenosis (DOLV VSD PS) (n = 5). The choice of the procedure was governed by various factors, including type of cardiac defect, pulmonary artery pressure and morphology, previous operation, socio-economic constraints and availability of appropriate sized homografts. Non-circuit operations may prevent future reoperations in these patients.

Surgical experience with total correction of tetralogy of Fallot in infancy

Fifty two patients less than one year old with tetralogy of Fallot underwent primary repair between January 1991 and December 1994. Age range was three to twelve months (mean 10.09 +/- 2.01 months) and body weight ranged from 4.5 to 9 kg (mean 8.38 +/- 2.79 kg). Transatrial-transpulmonary repair was performed in 36 patients and the classical transventricular approach was used in 16 patients. Six patients underwent emergency surgery for severe cyanosis and spells. Five patients had left pulmonary artery plasty for pulmonary artery bifurcation stenosis and two out of the five patients who had anomalous coronary arteries needed a right ventricle to pulmonary artery conduit. Mean post repair peak right ventricular/systemic pressure ratio was 0.74 +/- 0.18 in the transventricular group and 0.71 +/- 0.26 in the transatrial-transpulmonary group. There were three hospital deaths. Follow-up ranged from 3 to 46 months (mean 21.18 months). Forty patients underwent echocardiography and twenty patients underwent cardiac catheterisation six to eighteen months after surgery. Mean right ventricular outflow tract gradient on echocardiography was 20.35 +/- 10.12 and, at cardiac catheterisation, 17.51 +/- 13.49 mmHg with mean post repair peak right ventricle/left ventricle pressure ratio of 0.44 +/- 0.11. These were significantly less than the values obtained in the operating room. Only one patient had residual ventricular septal defect with left to right shunt of 1.6:1 at cardiac recatheterisation. There was one late death after reoperation for residual obstruction. Encouraging results with primary repair of tetralogy of Fallot in infancy prompt us to continue this policy in suitable cases.

Studies on the delineation of the hormone-specific antigenic determinants of human follicle-stimulating hormone

Human follicle-stimulating hormone (hFSH) is a key hormone regulating both male and female reproduction. The present study attempts to delineate the hFSH-specific antigenic determinants on its beta-subunit. Predictive methods were used to identify the potential surface-oriented regions of hFSH-beta. Peptides corresponding to these regions, namely, 31-52, 66-75 and 86-95 hFSH-beta, were synthesized and conjugated to diphtheria toxoid. Antipeptide antibodies, elicited in rabbits by immunization with the conjugates, were screened for their ability to bind to hFSH-beta and hFSH. Anti-31-52 hFSH-beta antisera bound to both hFSH-beta and hFSH, whereas anti-66-75 and anti-86-95 hFSH-beta antisera did not show any detectable binding. Furthermore, screening of anti-hFSH antisera showed significant binding only to 31-52 hFSH-beta. These results identify the region 31-52 hFSH-beta as a hormone-specific antigenic determinant of hFSH.

Comparison of antibodies raised against the peptide 10-24 of chicken riboflavin carrier protein (cRCP) by classical and multiple antigen peptide (MAP) approaches

Riboflavin carrier protein is an essential protein required for the growth and development of the embryo and hence for the maintenance of pregnancy. Our efforts to delineate the antigenic determinants of chicken riboflavin carrier protein (cRCP) resulted in the identification of a bioneutralization epitope in the region 10-24 of cRCP. The present work compares the properties of the antibodies raised against the peptide epitope by classical and multiple antigen peptide (MAP) system approaches. The extent of cross-reaction of the antibodies to the MAP construct with the parent protein was found to be significantly less as compared to the antibodies raised against the peptide-diphtheria toxoid conjugate. Furthermore, the bioneutralizing ability of the antisera to the MAP construct was also found to be very poor. The results suggest that there are serious limitations in the ability of antibodies raised against MAP constructs to cross-react with the native proteins.

Univentricular repair. Early and midterm results

A total of 202 patients (62 with tricuspid atresia and 140 without tricuspid atresia) underwent univentricular repair at our unit from January 1990 to September 1994. Of these patients, 182 had nonfenestrated and 20 had fenestrated interatrial baffles. Early mortality was 15.9% (29/182) in the group with nonfenestrated baffles and 5% (1/20) in the group with fenestrated baffles. The follow-up period ranged from 2 to 58 months. Seven late deaths occurred, and five patients were lost to follow-up. Of 160 patients who have been evaluated in the outpatient department in the past 3 months, 142 (88.75%) required no cardiac medicines and were in functional class I. Risk factors analyzed for early mortality and significant effusion were age, preoperative diagnosis, type of Fontan modification, cardiopulmonary bypass time, aortic crossclamp time, pulmonary artery size, associated pulmonary arterioplasty, takedown of systemic-pulmonary artery shunt, and pulmonary artery debanding, along with the Fontan operation. Bypass time exceeding 120 minutes was associated with a higher early mortality (12/47 vs 18/155; p = 0.0187). Bypass time exceeding 120 minutes (p = 0.0456) and aortic crossclamp time exceeding 60 minutes (p = 0.0278) were associated with significant postoperative effusion. Other factors were not associated with any significantly increased risk for early mortality or postoperative effusions. Fenestration of the interatrial baffle appeared to decrease early mortality, although the numbers are too small to be statistically significant. The prevalence of effusions did not differ significantly between the group with fenestrated baffles and the group without fenestrated baffles.

Serial echocardiography for decision making in rapid two-stage arterial switch operation

BACKGROUND

Rapid two-stage arterial switch operation is advocated in infants with simple transposition presenting late. Accurate assessment of left ventricular preparation is crucial to successful outcome. The role of echocardiography alone in surgical decision making remains unclear.

METHODS

Seventeen patients with simple transposition (mean age, 4 months) underwent pulmonary artery banding and modified Blalock-Taussig shunt (first stage) to prepare the left ventricle for the arterial switch operation (second stage). Serial echocardiography was performed in the interval phase to assess left ventricular growth. Sixteen patients underwent arterial switch operation after a mean interval of 10.4 +/- 4 days, with 14 successful conversions. There was one mortality (5.9%) and two conversions to a Senning repair.

RESULTS

In all patients a mean increase in left ventricular mass (40.8 +/- 17.8 g/m2 to 81.4 +/- 25.4 g/m2) and posterior wall thickness (3.37 +/- 0.47 mm to 4.63 +/- 0.58 mm) was recorded. Left ventricular end-diastolic internal diameter increased in all except the two switch failures. In all the successful cases the left ventricle had assumed a circular shape on cross-section with the interventricular septum contracting in synergy with the left ventricular mass. In the two failures, however, the interventricular septum had remained flat.

CONCLUSIONS

Echocardiography can be used reliably in surgical decision making in rapid two-stage arterial switch operation. Increase in left ventricular mass, left ventricular posterior wall thickness, and left ventricular end-diastolic internal diameter toward normal combined with an acquisition of circular left ventricular configuration with the interventricular septum contracting in synergy with the left ventricular mass appear to best predict successful outcome.

Polymerization of hemoglobin S. Quinary interactions of Glu-43(beta)

Hemoglobin S (HbS) Hoshida and three substituted forms of HbS Hoshida (the substituents being on the amide nitrogen of Gln-43(beta) have been prepared by the amidation of Glu-43(beta) of HbS with ammonia, methylamine, glycine ethyl ester, and galactosamine. The O2 affinity of HbS is increased slightly on amidation of Glu-43(beta). All the four amidated derivatives exhibited nearly the same oxygen affinity. On the other hand, the influence of amidation on the solubility exhibits some sensitivity to the chemical nature of the substituent on the Gln-43(beta). The solubility of HbS Hoshida (a case with no substitution on Gln-43(beta), and the methyl-substituted derivatives are about 33 and 36% higher than that of HbS. The solubility of the HbS modified with the glycine ethyl ester or galactosamine is increased to 41 and 47%, respectively. The first derivative UV spectra of HbS Hoshida and its methyl derivative reflect very little perturbations in their alpha 1 beta 2 interface as compared with that of HbS, whereas the amidated derivatives with larger substituents on Gln-43(beta) reflected noticeable difference. Thus, the increase in the solubility and the oxygen affinity of HbS on the amidation of Glu-43(beta) is primarily a consequence of the loss of the negative charge at 43(beta), a residue proximal to the alpha 1 beta 2 interface. The copolymerization studies of amidated HbS with HbA, and HbS with amidated HbA demonstrate that cis Glu-43(beta) is the "active" residue. This assignment is discrepant with the earlier implication of a trans configuration for this residue in the polymer (Edelstein, S. J. (1981) J. Mol. Biol. 150, 557-575). However, it is consistent with the solution studies of Nagel et al. (Nagel, R. L., Bookchin, R. M., Johnson, J., Labie, D., Wajcman, H.., Isaac-Sodeye, W. A., Honig, G. R., Schiliro, G., Crookstan, J. H., and Matsutomo, K. (1979) Proc. Nat. Acad. Sci. U.S.A. 76, 670-672) and McCurdy et al. (McCurdy, P. R., Lorkin, P. A., Casey, R., Lehmann, H., Uddin, D. E., and Dickson, L. G. (1974) Am. J. Med. 57, 665-760).

The right ventricle to pulmonary artery connection: when homografts are not always available

Aortic or pulmonary homografts are currently the most popular conduits for correction of right ventricle to pulmonary artery (RV-PA) discontinuity. Problems of nonavailability or limited supply in developing countries, however, necessitate recourse to other forms of repair. Forty-nine patients of 72 with RV-PA discontinuity underwent repair without use of a homograft at our institution over a 5-year period. Handmade pericardial valved conduits (n = 18), nonvalved tubes (n = 13), and nonconduit procedures like the REV operation (n = 11) and extended pericardial gusset (n = 5) were mainly used. The choice of procedure was governed by various factors including type of cardiac defect, pulmonary artery pressure and morphology, previous operation, and socioeconomic constraints. Extracardiac conduits do not provide a permanent solution to the problem of RV-PA discontinuity, and efforts to innovate and refine nonconduit procedures must continue.

Orthotopic pulmonary valve replacement with a homograft

Eight pulmonary valve replacements (PVR) have been performed from January 1992 to October 1994. Three patients (mean age 7.7 years, range two to 16 years) had absent pulmonary valve with tetralogy of Fallot and underwent primary PVR at the time of surgical correction. Five other patients, who had correction of tetralogy of Fallot (four cases) and of double outlet right ventricle with ventricular septal defect and pulmonary stenosis (one case), were reoperated for pulmonary regurgitation with progressive right ventricular dysfunction. Mean age at the time of reoperation was 18 years (range seven to 34 years). There was no early death. Early postoperative recovery was satisfactory in all of them. The follow up ranges from six to 35 months (mean 19 months). Seven patients were in functional class I and one in functional class II when they were last evaluated in the out-patient department and five of them were off diuretics and vasodilator. In the presence of right ventricular dysfunction pulmonary regurgitation is poorly tolerated. A competent and non-obstructive pulmonary valve is often life saving in these critically ill patients.

Termination of pregnancy in mice following administration of antibodies to the pentadecapeptide 10-24 of chicken riboflavin carrier protein: identification of a bioneutralizing epitope of chicken riboflavin carrier protein

Our studies have shown that the administration of antibodies to chicken riboflavin carrier protein (cRCP) or disulfide-reduced carboxymethylated cRCP (RCM-RCP) leads to termination of pregnancy in mice. In an attempt to delineate the bioneutralizing epitopes, a combination of chemical modification and predictive methods was used. The results led to the identification of the region 10-24 of cRCP as a potential candidate. A single injection of antipeptide antibodies to pregnant mice on day 11 resulted in 100% pregnancy termination. This was accompanied by a drastic reduction in circulatory progesterone as early as 24 h after the antibody administration. These results thus demonstrate that the amino acid sequence 10-24 of cRCP harbours a bioneutralizing epitope of cRCP.

Enhanced lipid peroxidation in patients during coronary artery bypass grafting

Lipid peroxidation products were measured at various time intervals in 20 patients with coronary artery disease, who underwent coronary artery bypass graft (CABG) surgery. Post-operative blood lipid peroxides were found to be significantly higher (p < 0.001) than the preoperative value. Lipid peroxides raised to a peak value of 46.42 +/- 12.86 n mol/g Alb at 5 min of reperfusion when compared to the basal value and afterwards the level declined to 41.02 +/- 7.09 at 2 hrs and remained in that level even at 24 hrs of reperfusion. This increase implies an enhancement in free radical mediated oxidation of membrane lipids during bypass surgery and thus provides evidence for free radical generation during myocardial reperfusion.

Studies on the carboxyl terminal peptides of human seminal plasma inhibin (HSPI). Chemical synthesis and in vivo biological activity of the disulfide loop peptide 67-94 of HSPI

Observation of contradictory results with the in vitro assays for inhibin-like activity of the carboxyl terminal 28 amino acid peptide 67-94 with a disulfide loop, of human seminal plasma inhibin (HSPI), prompted us to synthesize both the linear and the cyclic peptides and test their ability to suppress the circulating levels of follicle stimulating hormone (FSH) in vivo in adult male rats. The linear peptide [Cys(Acm)73,87] 67-94 of HSPI was synthesized by solid-phase peptide synthesis using fluorenylmethyloxycarbonyl (Fmoc) chemistry and a continuous-flow technology. The peptide was cyclized by direct iodine oxidation of the S-diacetamidomethyl peptide in dilute solution. In the in vivo assay the linear peptide did not affect the levels of FSH, whereas the cyclic peptide suppressed the levels of FSH significantly. Thus, the carboxyl terminal region of HSPI does have inhibin-like activity and perhaps has the active core of the protein.

Distribution of cholesterol in HDL and its subfractions in patients with coronary atherosclerotic heart disease

The distribution of HDL-C and its subclasses HDL3-C and HDL2-C and other serum lipids was studied in patients with coronary atherosclerotic heart disease grouped as young males (group 1) and older males (group 2) along with age matched controls. All the patients had significantly higher levels of serum cholesterol, triglycerides, LDL-C and VLDL-C and lower levels of HDL-C. The analysis of HDL - subclasses clearly demonstrated that the low levels of HDL-C was due to the significant decrease of cholesterol in both HDL3 (group 1: 32%; group 2: 30%) and HDL2 subclasses (group 1: 55%; group 2: 48%) compared to the respective control values. Further it has also been observed that this low level of HDL-C is a characteristic feature of patients irrespective of whether the levels of serum cholesterol and triglycerides are high or normal. Although both the HDL subclasses were decreased, the percentage of reduction of cholesterol was greater in the HDL2 than in HDL3 subclass. In addition, the levels of cholesterol either in HDL or any of its subclasses, HDL3 and HDL2 did not show any change in relation to the extent of coronary disease which was assessed by coronary angiography. This study confirms the inverse relation of HDL-C with coronary atherosclerosis and also indicates that, of all the lipid parameters examined, only HDL-C, particularly its subclass HDL2-C, shows independent inverse relation to the incidence of coronary atherosclerotic artery disease in men.

Studies on the delineation of the antigenic determinants of chicken riboflavin carrier protein (cRCP). Identification of a determinant in the region 10-24 of the protein

As riboflavin carrier proteins play a critical role in the maintenance of pregnancy, studies on the immunology of these proteins have become very relevant. This paper describes our attempts to identify the sequential antigenic determinants of chicken riboflavin carrier protein (cRCP). Potential surface oriented regions of cRCP were identified by constructing acrophilicity and hydrophilicity profiles of the protein. Of the three regions identified, the pentadecapeptide 10-24 of cRCP forms the subject of the present study. The pentadecapeptide amide was synthesized by solid phase synthesis using Fmoc chemistry. Immunization of rabbits with the peptide-diphtheria toxoid conjugate elicited high titres of the antipeptide antibodies, revealing the high immunogenicity of the peptide. The antipeptide antibodies bound to both cRCP and reduced carboxymethylated RCP (RCM-RCP). Antisera to RCM-RCP showed significant binding to the peptide showing thereby that the region 10-24 of cRCP is perhaps one of the major epitopes of RCM-RCP. Thus, the studies have resulted in the identification of the region 10-24 as an antigenic determinant of cRCP.